diff --git a/BUILD.bazel b/BUILD.bazel
index 6f360e0828..e8a26c5709 100644
--- a/BUILD.bazel
+++ b/BUILD.bazel
@@ -1,17 +1,14 @@
 # Bazel (https://bazel.build/) BUILD file for Protobuf.
 
 load("@bazel_skylib//rules:common_settings.bzl", "string_flag")
-load("@rules_cc//cc:defs.bzl", "cc_binary", "cc_library", "cc_proto_library","cc_test")
+load("@rules_cc//cc:defs.bzl", "cc_binary", "cc_library", "cc_proto_library", "cc_test")
 load("@rules_pkg//:mappings.bzl", "pkg_files", "strip_prefix")
 load("@rules_proto//proto:defs.bzl", "proto_lang_toolchain", "proto_library")
-load("@rules_python//python:defs.bzl", "py_library")
 load("@rules_java//java:defs.bzl", "java_binary", "java_lite_proto_library", "java_proto_library")
 load("//build_defs:cpp_opts.bzl", "COPTS", "LINK_OPTS")
 load(
     ":protobuf.bzl",
     "adapt_proto_library",
-    "internal_copied_filegroup",
-    "internal_protobuf_py_tests",
     "py_proto_library",
 )
 
@@ -538,9 +535,15 @@ RELATIVE_TEST_PROTOS = [
 
 TEST_PROTOS = ["src/" + s for s in RELATIVE_TEST_PROTOS]
 
+filegroup(
+    name = "test_proto_srcs",
+    srcs = TEST_PROTOS,
+    visibility = ["//:__subpackages__"],
+)
+
 proto_library(
     name = "test_protos",
-    srcs = TEST_PROTOS,
+    srcs = [":test_proto_srcs"],
     strip_import_prefix = "src",
     visibility = ["//:__subpackages__"],
     deps = [
@@ -819,264 +822,40 @@ alias(
 # Python support
 ################################################################################
 
-py_library(
+alias(
+    name = "protobuf_python",
+    actual = "//python:protobuf_python",
+    visibility = ["//visibility:public"],
+)
+
+alias(
     name = "python_srcs",
-    srcs = glob(
-        [
-            "python/google/protobuf/**/*.py",
-        ],
-    ),
-    imports = ["python"],
-    srcs_version = "PY2AND3",
+    actual = "//python:python_srcs",
     visibility = ["@upb//:__subpackages__"],
 )
 
-py_library(
+alias(
     name = "python_test_srcs",
-    srcs = glob(
-        [
-            "python/google/protobuf/internal/*_test.py",
-            "python/google/protobuf/internal/test_util.py",
-        ],
-    ),
-    imports = ["python"],
-    srcs_version = "PY3",
+    actual = "//python:python_test_srcs",
     visibility = ["@upb//:__subpackages__"],
 )
 
-cc_binary(
-    name = "python/google/protobuf/internal/_api_implementation.so",
-    srcs = ["python/google/protobuf/internal/api_implementation.cc"],
-    copts = COPTS + [
-        "-DPYTHON_PROTO2_CPP_IMPL_V2",
-    ],
-    linkshared = 1,
-    linkstatic = 1,
-    tags = [
-        # Exclude this target from wildcard expansion (//...) because it may
-        # not even be buildable. It will be built if it is needed according
-        # to :use_fast_cpp_protos.
-        # https://docs.bazel.build/versions/master/be/common-definitions.html#common-attributes
-        "manual",
-    ],
-    deps = select({
-        "//conditions:default": [],
-        ":use_fast_cpp_protos": ["//external:python_headers"],
-    }),
-)
-
-cc_binary(
-    name = "python/google/protobuf/pyext/_message.so",
-    srcs = glob([
-        "python/google/protobuf/pyext/*.cc",
-        "python/google/protobuf/pyext/*.h",
-    ]),
-    copts = COPTS + [
-        "-DGOOGLE_PROTOBUF_HAS_ONEOF=1",
-    ] + select({
-        "//conditions:default": [],
-        ":allow_oversize_protos": ["-DPROTOBUF_PYTHON_ALLOW_OVERSIZE_PROTOS=1"],
-    }),
-    includes = [
-        "python/",
-        "src/",
-    ],
-    linkshared = 1,
-    linkstatic = 1,
-    tags = [
-        # Exclude this target from wildcard expansion (//...) because it may
-        # not even be buildable. It will be built if it is needed according
-        # to :use_fast_cpp_protos.
-        # https://docs.bazel.build/versions/master/be/common-definitions.html#common-attributes
-        "manual",
-    ],
-    deps = [
-        ":protobuf",
-        ":proto_api",
-    ] + select({
-        "//conditions:default": [],
-        ":use_fast_cpp_protos": ["//external:python_headers"],
-    }),
-)
-
-config_setting(
-    name = "use_fast_cpp_protos",
-    values = {
-        "define": "use_fast_cpp_protos=true",
-    },
-    visibility = [
-        # Public, but Protobuf only visibility.
-        "//:__subpackages__",
-    ],
-)
-
-config_setting(
-    name = "allow_oversize_protos",
-    values = {
-        "define": "allow_oversize_protos=true",
-    },
-    visibility = [
-        # Public, but Protobuf only visibility.
-        "//:__subpackages__",
-    ],
-)
-
-# Copy the builtin proto files from src/google/protobuf to
-# python/google/protobuf. This way, the generated Python sources will be in the
-# same directory as the Python runtime sources. This is necessary for the
-# modules to be imported correctly since they are all part of the same Python
-# package.
-internal_copied_filegroup(
-    name = "protos_python",
-    srcs = [
-        "src/google/protobuf/any.proto",
-        "src/google/protobuf/api.proto",
-        "src/google/protobuf/compiler/plugin.proto",
-        "src/google/protobuf/descriptor.proto",
-        "src/google/protobuf/duration.proto",
-        "src/google/protobuf/empty.proto",
-        "src/google/protobuf/field_mask.proto",
-        "src/google/protobuf/source_context.proto",
-        "src/google/protobuf/struct.proto",
-        "src/google/protobuf/timestamp.proto",
-        "src/google/protobuf/type.proto",
-        "src/google/protobuf/wrappers.proto",
-    ],
-    dest = "python",
-    strip_prefix = "src",
-)
-
-py_proto_library(
+alias(
     name = "well_known_types_py_pb2",
-    srcs = [
-        "python/google/protobuf/any.proto",
-        "python/google/protobuf/api.proto",
-        "python/google/protobuf/compiler/plugin.proto",
-        "python/google/protobuf/descriptor.proto",
-        "python/google/protobuf/duration.proto",
-        "python/google/protobuf/empty.proto",
-        "python/google/protobuf/field_mask.proto",
-        "python/google/protobuf/source_context.proto",
-        "python/google/protobuf/struct.proto",
-        "python/google/protobuf/timestamp.proto",
-        "python/google/protobuf/type.proto",
-        "python/google/protobuf/wrappers.proto",
-    ],
-    include = "python",
-    default_runtime = "",
-    protoc = ":protoc",
-    srcs_version = "PY2AND3",
+    actual = "//python:well_known_types_py_pb2",
     visibility = ["@upb//:__subpackages__"],
 )
 
-py_library(
-    name = "protobuf_python",
-    data = select({
-        "//conditions:default": [],
-        ":use_fast_cpp_protos": [
-            ":python/google/protobuf/internal/_api_implementation.so",
-            ":python/google/protobuf/pyext/_message.so",
-        ],
-    }),
-    deps = [
-        ":python_srcs",
-        ":well_known_types_py_pb2",
-    ],
-)
-
-# Copy the test proto files from src/google/protobuf to
-# python/google/protobuf. This way, the generated Python sources will be in the
-# same directory as the Python runtime sources. This is necessary for the
-# modules to be imported correctly by the tests since they are all part of the
-# same Python package.
-internal_copied_filegroup(
-    name = "protos_python_test",
-    srcs = LITE_TEST_PROTOS + TEST_PROTOS,
-    dest = "python",
-    strip_prefix = "src",
-)
-
-# TODO(dzc): Remove this once py_proto_library can have labels in srcs, in
-# which case we can simply add :protos_python_test in srcs.
-COPIED_LITE_TEST_PROTOS = ["python/" + s for s in RELATIVE_LITE_TEST_PROTOS]
-
-COPIED_TEST_PROTOS = ["python/" + s for s in RELATIVE_TEST_PROTOS]
-
-py_proto_library(
+alias(
     name = "python_common_test_protos",
-    srcs = COPIED_LITE_TEST_PROTOS + COPIED_TEST_PROTOS,
-    include = "python",
-    default_runtime = "",
-    protoc = ":protoc",
-    srcs_version = "PY2AND3",
+    actual = "//python:python_common_test_protos",
     visibility = ["//visibility:public"],
-    deps = [":well_known_types_py_pb2"],
 )
 
-py_proto_library(
+alias(
     name = "python_specific_test_protos",
-    srcs = glob([
-        "python/google/protobuf/internal/*.proto",
-        "python/google/protobuf/internal/import_test_package/*.proto",
-    ]),
-    include = "python",
-    default_runtime = ":protobuf_python",
-    protoc = ":protoc",
-    srcs_version = "PY2AND3",
+    actual = "//python:python_specific_test_protos",
     visibility = ["//visibility:public"],
-    deps = [":python_common_test_protos"],
-)
-
-py_library(
-    name = "python_tests",
-    srcs = glob(
-        [
-            "python/google/protobuf/internal/*_test.py",
-            "python/google/protobuf/internal/test_util.py",
-            "python/google/protobuf/internal/import_test_package/__init__.py",
-        ],
-    ),
-    imports = ["python"],
-    srcs_version = "PY2AND3",
-    deps = [
-        ":protobuf_python",
-        ":python_common_test_protos",
-        ":python_specific_test_protos",
-    ],
-)
-
-internal_protobuf_py_tests(
-    name = "python_tests_batch",
-    data = glob([
-        "src/google/protobuf/**/*",
-    ]),
-    modules = [
-        "descriptor_database_test",
-        "descriptor_pool_test",
-        "descriptor_test",
-        "generator_test",
-        "json_format_test",
-        "message_factory_test",
-        "message_test",
-        "proto_builder_test",
-        "reflection_test",
-        "service_reflection_test",
-        "symbol_database_test",
-        "text_encoding_test",
-        "text_format_test",
-        "unknown_fields_test",
-        "wire_format_test",
-    ],
-    deps = [":python_tests"],
-)
-
-cc_library(
-    name = "proto_api",
-    hdrs = ["python/google/protobuf/proto_api.h"],
-    visibility = ["//visibility:public"],
-    deps = [
-        "//external:python_headers",
-    ],
 )
 
 proto_lang_toolchain(
@@ -1122,25 +901,21 @@ genrule(
     name = "generated_protos",
     srcs = ["src/google/protobuf/unittest_import.proto"],
     outs = ["unittest_gen_import.proto"],
-    cmd = "cat $(SRCS) | sed 's|google/|src/google/|' >  $(OUTS)",
+    cmd = "cat $(SRCS) >  $(OUTS)",
 )
 
 proto_library(
     name = "generated_protos_proto",
-    srcs = [
-        "src/google/protobuf/unittest_import_public.proto",
-        "unittest_gen_import.proto",
-    ],
+    srcs = [":generated_protos"],
+    deps = [":generic_test_protos"],
 )
 
 py_proto_library(
     name = "generated_protos_py",
-    srcs = [
-        "src/google/protobuf/unittest_import_public.proto",
-        "unittest_gen_import.proto",
-    ],
+    srcs = [":generated_protos"],
     default_runtime = "",
     protoc = ":protoc",
+    deps = ["//python:python_common_test_protos"],
 )
 
 ################################################################################
@@ -1361,29 +1136,3 @@ pkg_files(
     ],
     visibility = ["//pkg:__pkg__"],
 )
-
-# Python runtime
-pkg_files(
-    name = "python_dist_files",
-    srcs = glob([
-        "python/google/**/*.proto",
-        "python/google/**/*.py",
-        "python/google/protobuf/internal/*.cc",
-        "python/google/protobuf/pyext/*.cc",
-        "python/google/protobuf/pyext/*.h",
-    ]) + [
-        "python/MANIFEST.in",
-        "python/README.md",
-        "python/google/protobuf/proto_api.h",
-        "python/google/protobuf/pyext/README",
-        "python/google/protobuf/python_protobuf.h",
-        "python/mox.py",
-        "python/release.sh",
-        "python/setup.cfg",
-        "python/setup.py",
-        "python/stubout.py",
-        "python/tox.ini",
-    ],
-    strip_prefix = strip_prefix.from_root(""),
-    visibility = ["//pkg:__pkg__"],
-)
diff --git a/Makefile.am b/Makefile.am
index 22c85a4059..7f064294b6 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -993,6 +993,7 @@ php_EXTRA_DIST=                                                       \
 
 # Note: please keep this in sync with the python_dist_files rule in BUILD.bazel.
 python_EXTRA_DIST=                                                           \
+  python/BUILD.bazel                                                         \
   python/MANIFEST.in                                                         \
   python/google/__init__.py                                                  \
   python/google/protobuf/__init__.py                                         \
@@ -1107,6 +1108,7 @@ python_EXTRA_DIST=                                                           \
   python/google/protobuf/text_format.py                                      \
   python/google/protobuf/unknown_fields.py                                   \
   python/google/protobuf/util/__init__.py                                    \
+  python/internal.bzl                                                        \
   python/release.sh                                                          \
   python/mox.py                                                              \
   python/setup.cfg                                                           \
diff --git a/kokoro/common/check_missing_dist_files.sh b/kokoro/common/check_missing_dist_files.sh
index 0bb26ad34b..db4d92fc11 100755
--- a/kokoro/common/check_missing_dist_files.sh
+++ b/kokoro/common/check_missing_dist_files.sh
@@ -50,6 +50,6 @@ fi
   for (( i=0 ; i < ${#MISSING_FILES[@]} ; i++ )); do
     echo "  ${MISSING_FILES[i]}"
   done
-  echo -e "\nAdd them to the `pkg_files` rule in corresponding BUILD.bazel.\n"
+  echo -e "\nAdd them to the 'pkg_files' rule in corresponding BUILD.bazel.\n"
 ) >&2
 exit 1
diff --git a/kokoro/linux/bazel_distcheck/build.sh b/kokoro/linux/bazel_distcheck/build.sh
index 4eb6e11264..740a4aba87 100755
--- a/kokoro/linux/bazel_distcheck/build.sh
+++ b/kokoro/linux/bazel_distcheck/build.sh
@@ -18,9 +18,14 @@ TEST_TARGETS=(
   //build_defs:all
   //conformance:all
   //java:tests
+  //python:all
   //:protobuf_test
+  @com_google_protobuf_examples//...
 )
 
+CONTAINER_NAME=gcr.io/protobuf-build/bazel/linux
+CONTAINER_VERSION=5.1.1-e41ccfa1648716433276ebe077c665796550fcbb
+
 use_bazel.sh 5.0.0 || true
 bazel version
 
@@ -65,20 +70,17 @@ tar -C ${DIST_WORKSPACE} --strip-components=1 -axf ${DIST_ARCHIVE}
 cd ${DIST_WORKSPACE}
 FAILED=false
 
-date
-bazel fetch --distdir=${TMP_DISTDIR} "${BUILD_ONLY_TARGETS[@]}" "${TEST_TARGETS[@]}"
-
-date
-bazel build --distdir=${TMP_DISTDIR} -k \
-  "${BUILD_ONLY_TARGETS[@]}" || FAILED=true
-
-date
-bazel test --distdir=${TMP_DISTDIR} --test_output=errors -k \
-  "${TEST_TARGETS[@]}" || FAILED=true
+until docker pull gcr.io/protobuf-build/bazel/linux:${CONTAINER_VERSION}; do
+  sleep 10
+done
 
 date
-cd examples
-bazel build --distdir=${TMP_DISTDIR} //... || FAILED=true
+docker run --rm \
+  -v ${DIST_WORKSPACE}:/workspace \
+  -v ${TMP_DISTDIR}:${TMP_DISTDIR} \
+  ${CONTAINER_NAME}:${CONTAINER_VERSION} \
+  test --distdir=${TMP_DISTDIR} --test_output=errors -k \
+  "${BUILD_ONLY_TARGETS[@]}" "${TEST_TARGETS[@]}" || FAILED=true
 
 if ${FAILED}; then
    echo FAILED
diff --git a/pkg/BUILD.bazel b/pkg/BUILD.bazel
index 0de27d3a27..e4899445cc 100644
--- a/pkg/BUILD.bazel
+++ b/pkg/BUILD.bazel
@@ -238,7 +238,7 @@ pkg_filegroup(
     name = "python_srcs",
     srcs = [
         ":dist_common",
-        "//:python_dist_files",
+        "//python:dist_files",
     ],
 )
 
@@ -342,7 +342,7 @@ gen_automake_file_lists(
         "//:objectivec_dist_files": "dist_objectivec",
         "//objectivec:dist_files": "dist_objectivec2",
         "//php:dist_files": "dist_php",
-        "//:python_dist_files": "dist_python",
+        "//python:dist_files": "dist_python",
         "//ruby:dist_files": "dist_ruby",
     },
 )
@@ -360,6 +360,7 @@ cc_dist_library(
     deps = [
         "//:protobuf_lite",
     ],
+    tags = ["manual"],
 )
 
 cc_dist_library(
@@ -375,6 +376,7 @@ cc_dist_library(
         "//:protobuf",
         "//:protobuf_lite",
     ],
+    tags = ["manual"],
 )
 
 ################################################################################
diff --git a/protobuf.bzl b/protobuf.bzl
index 1fbd747efc..7981c50f03 100644
--- a/protobuf.bzl
+++ b/protobuf.bzl
@@ -58,21 +58,6 @@ def _PyOuts(srcs, use_grpc_plugin = False):
         ret += [s[:-len(".proto")] + "_pb2_grpc.py" for s in srcs]
     return ret
 
-def _RelativeOutputPath(path, include, dest = ""):
-    if include == None:
-        return path
-
-    if not path.startswith(include):
-        fail("Include path %s isn't part of the path %s." % (include, path))
-
-    if include and include[-1] != "/":
-        include = include + "/"
-    if dest and dest[-1] != "/":
-        dest = dest + "/"
-
-    path = path[len(include):]
-    return dest + path
-
 ProtoGenInfo = provider(
     fields = ["srcs", "import_flags", "deps"],
 )
@@ -469,41 +454,6 @@ internal_gen_kt_protos = rule(
     },
 )
 
-def internal_copied_filegroup(name, srcs, strip_prefix, dest, **kwargs):
-    """Macro to copy files to a different directory and then create a filegroup.
-
-    This is used by the //:protobuf_python py_proto_library target to work around
-    an issue caused by Python source files that are part of the same Python
-    package being in separate directories.
-
-    Args:
-      srcs: The source files to copy and add to the filegroup.
-      strip_prefix: Path to the root of the files to copy.
-      dest: The directory to copy the source files into.
-      **kwargs: extra arguments that will be passesd to the filegroup.
-    """
-    outs = [_RelativeOutputPath(s, strip_prefix, dest) for s in srcs]
-
-    native.genrule(
-        name = name + "_genrule",
-        srcs = srcs,
-        outs = outs,
-        cmd_bash = " && ".join(
-            ["cp $(location %s) $(location %s)" %
-             (s, _RelativeOutputPath(s, strip_prefix, dest)) for s in srcs],
-        ),
-        cmd_bat = " && ".join(
-            ["@copy /Y $(location %s) $(location %s) >NUL" %
-             (s, _RelativeOutputPath(s, strip_prefix, dest)) for s in srcs],
-        ),
-    )
-
-    native.filegroup(
-        name = name,
-        srcs = outs,
-        **kwargs
-    )
-
 def py_proto_library(
         name,
         srcs = [],
@@ -571,28 +521,6 @@ def py_proto_library(
         **kargs
     )
 
-def internal_protobuf_py_tests(
-        name,
-        modules = [],
-        **kargs):
-    """Bazel rules to create batch tests for protobuf internal.
-
-    Args:
-      name: the name of the rule.
-      modules: a list of modules for tests. The macro will create a py_test for
-          each of the parameter with the source "google/protobuf/%s.py"
-      kargs: extra parameters that will be passed into the py_test.
-
-    """
-    for m in modules:
-        s = "python/google/protobuf/internal/%s.py" % m
-        py_test(
-            name = "py_%s" % m,
-            srcs = [s],
-            main = s,
-            **kargs
-        )
-
 def check_protobuf_required_bazel_version():
     """For WORKSPACE files, to check the installed version of bazel.
 
diff --git a/python/BUILD.bazel b/python/BUILD.bazel
new file mode 100644
index 0000000000..6316febca7
--- /dev/null
+++ b/python/BUILD.bazel
@@ -0,0 +1,351 @@
+# Protobuf Python runtime
+#
+# See also code generation logic under /src/google/protobuf/compiler/python.
+#
+# Most users should depend upon public aliases in the root:
+#   //:protobuf_python
+#   //:well_known_types_py_pb2
+
+load("@rules_pkg//:mappings.bzl", "pkg_files", "strip_prefix")
+load("@rules_proto//proto:defs.bzl", "proto_library")
+load("@rules_python//python:defs.bzl", "py_library")
+load("//:protobuf.bzl", "py_proto_library")
+load("//build_defs:cpp_opts.bzl", "COPTS")
+load(":internal.bzl", "internal_copy_files")
+
+py_library(
+    name = "protobuf_python",
+    data = select({
+        "//conditions:default": [],
+        ":use_fast_cpp_protos": [
+            ":google/protobuf/internal/_api_implementation.so",
+            ":google/protobuf/pyext/_message.so",
+        ],
+    }),
+    visibility = ["//:__pkg__"],
+    deps = [
+        ":python_srcs",
+        ":well_known_types_py_pb2",
+    ],
+)
+
+config_setting(
+    name = "use_fast_cpp_protos",
+    values = {
+        "define": "use_fast_cpp_protos=true",
+    },
+)
+
+py_proto_library(
+    name = "well_known_types_py_pb2",
+    srcs = [":copied_wkt_proto_files"],
+    include = ".",
+    default_runtime = "",
+    protoc = "//:protoc",
+    srcs_version = "PY2AND3",
+    visibility = [
+        "//:__pkg__",
+        "@upb//:__subpackages__",
+    ],
+)
+
+internal_copy_files(
+    name = "copied_wkt_proto_files",
+    srcs = [
+        "//:built_in_runtime_protos",
+        "//:well_known_type_protos",
+    ],
+    strip_prefix = "src",
+)
+
+cc_binary(
+    name = "google/protobuf/internal/_api_implementation.so",
+    srcs = ["google/protobuf/internal/api_implementation.cc"],
+    copts = COPTS + [
+        "-DPYTHON_PROTO2_CPP_IMPL_V2",
+    ],
+    linkshared = 1,
+    linkstatic = 1,
+    tags = [
+        # Exclude this target from wildcard expansion (//...) because it may
+        # not even be buildable. It will be built if it is needed according
+        # to :use_fast_cpp_protos.
+        # https://docs.bazel.build/versions/master/be/common-definitions.html#common-attributes
+        "manual",
+    ],
+    deps = select({
+        "//conditions:default": [],
+        ":use_fast_cpp_protos": ["//external:python_headers"],
+    }),
+)
+
+config_setting(
+    name = "allow_oversize_protos",
+    values = {
+        "define": "allow_oversize_protos=true",
+    },
+)
+
+cc_binary(
+    name = "google/protobuf/pyext/_message.so",
+    srcs = glob([
+        "google/protobuf/pyext/*.cc",
+        "google/protobuf/pyext/*.h",
+    ]),
+    copts = COPTS + [
+        "-DGOOGLE_PROTOBUF_HAS_ONEOF=1",
+    ] + select({
+        "//conditions:default": [],
+        ":allow_oversize_protos": ["-DPROTOBUF_PYTHON_ALLOW_OVERSIZE_PROTOS=1"],
+    }),
+    includes = ["."],
+    linkshared = 1,
+    linkstatic = 1,
+    tags = [
+        # Exclude this target from wildcard expansion (//...) because it may
+        # not even be buildable. It will be built if it is needed according
+        # to :use_fast_cpp_protos.
+        # https://docs.bazel.build/versions/master/be/common-definitions.html#common-attributes
+        "manual",
+    ],
+    deps = [
+        ":proto_api",
+        "//:protobuf",
+    ] + select({
+        "//conditions:default": [],
+        ":use_fast_cpp_protos": ["//external:python_headers"],
+    }),
+)
+
+py_library(
+    name = "python_srcs",
+    srcs = glob(
+        [
+            "google/protobuf/**/*.py",
+        ],
+        exclude = [
+            "google/protobuf/internal/*_test.py",
+            "google/protobuf/internal/test_util.py",
+            "google/protobuf/internal/import_test_package/__init__.py",
+        ],
+    ),
+    imports = ["python"],
+    srcs_version = "PY2AND3",
+    visibility = [
+        "//:__pkg__",
+        "@upb//:__subpackages__",
+    ],
+)
+
+py_library(
+    name = "python_test_srcs",
+    srcs = glob([
+        "google/protobuf/internal/*_test.py",
+    ]) + [
+        "google/protobuf/internal/test_util.py",
+        "google/protobuf/internal/import_test_package/__init__.py",
+    ],
+    imports = ["python"],
+    srcs_version = "PY3",
+    visibility = [
+        "//:__pkg__",
+        "@upb//:__subpackages__",
+    ],
+)
+
+################################################################################
+# Tests
+################################################################################
+
+internal_copy_files(
+    name = "copied_test_proto_files",
+    srcs = ["//:test_proto_srcs"],
+    strip_prefix = "src",
+)
+
+py_proto_library(
+    name = "python_common_test_protos",
+    srcs = [":copied_test_proto_files"],
+    include = ".",
+    default_runtime = "",
+    protoc = "//:protoc",
+    srcs_version = "PY2AND3",
+    visibility = ["//:__pkg__"],
+    deps = [":well_known_types_py_pb2"],
+)
+
+py_proto_library(
+    name = "python_specific_test_protos",
+    srcs = glob([
+        "google/protobuf/internal/*.proto",
+        "google/protobuf/internal/import_test_package/*.proto",
+    ]),
+    include = ".",
+    default_runtime = ":protobuf_python",
+    protoc = "//:protoc",
+    srcs_version = "PY2AND3",
+    visibility = ["//:__pkg__"],
+    deps = [":python_common_test_protos"],
+)
+
+py_library(
+    name = "python_test_lib",
+    srcs = [
+        "google/protobuf/internal/import_test_package/__init__.py",
+        "google/protobuf/internal/test_util.py",
+    ],
+    imports = ["python"],
+    srcs_version = "PY2AND3",
+    deps = [
+        ":protobuf_python",
+        ":python_common_test_protos",
+        ":python_specific_test_protos",
+    ],
+)
+
+py_test(
+    name = "descriptor_database_test",
+    srcs = ["google/protobuf/internal/descriptor_database_test.py"],
+    deps = [":python_test_lib"],
+)
+
+py_test(
+    name = "descriptor_pool_test",
+    srcs = ["google/protobuf/internal/descriptor_pool_test.py"],
+    deps = [":python_test_lib"],
+)
+
+py_test(
+    name = "descriptor_test",
+    srcs = ["google/protobuf/internal/descriptor_test.py"],
+    imports = ["."],
+    deps = [":python_test_lib"],
+)
+
+py_test(
+    name = "generator_test",
+    srcs = ["google/protobuf/internal/generator_test.py"],
+    imports = ["."],
+    deps = [":python_test_lib"],
+)
+
+py_test(
+    name = "json_format_test",
+    srcs = ["google/protobuf/internal/json_format_test.py"],
+    imports = ["."],
+    deps = [":python_test_lib"],
+)
+
+py_test(
+    name = "message_factory_test",
+    srcs = ["google/protobuf/internal/message_factory_test.py"],
+    imports = ["."],
+    deps = [":python_test_lib"],
+)
+
+py_test(
+    name = "message_test",
+    srcs = ["google/protobuf/internal/message_test.py"],
+    data = glob(["testdata/golden_pickle_*"]) + [
+        "//:testdata",
+    ],
+    imports = ["."],
+    deps = [":python_test_lib"],
+)
+
+py_test(
+    name = "proto_builder_test",
+    srcs = ["google/protobuf/internal/proto_builder_test.py"],
+    imports = ["."],
+    deps = [":python_test_lib"],
+)
+
+py_test(
+    name = "reflection_test",
+    srcs = ["google/protobuf/internal/reflection_test.py"],
+    imports = ["."],
+    deps = [":python_test_lib"],
+)
+
+py_test(
+    name = "service_reflection_test",
+    srcs = ["google/protobuf/internal/service_reflection_test.py"],
+    imports = ["."],
+    deps = [":python_test_lib"],
+)
+
+py_test(
+    name = "symbol_database_test",
+    srcs = ["google/protobuf/internal/symbol_database_test.py"],
+    imports = ["."],
+    deps = [":python_test_lib"],
+)
+
+py_test(
+    name = "text_encoding_test",
+    srcs = ["google/protobuf/internal/text_encoding_test.py"],
+    imports = ["."],
+    deps = [":python_test_lib"],
+)
+
+py_test(
+    name = "text_format_test",
+    srcs = ["google/protobuf/internal/text_format_test.py"],
+    data = ["//:testdata"],
+    imports = ["."],
+    deps = [":python_test_lib"],
+)
+
+py_test(
+    name = "unknown_fields_test",
+    srcs = ["google/protobuf/internal/unknown_fields_test.py"],
+    imports = ["."],
+    deps = [":python_test_lib"],
+)
+
+py_test(
+    name = "wire_format_test",
+    srcs = ["google/protobuf/internal/wire_format_test.py"],
+    imports = ["."],
+    deps = [":python_test_lib"],
+)
+
+cc_library(
+    name = "proto_api",
+    hdrs = ["python/google/protobuf/proto_api.h"],
+    visibility = ["//visibility:public"],
+    deps = [
+        "//external:python_headers",
+    ],
+)
+
+################################################################################
+# Distribution files
+################################################################################
+
+pkg_files(
+    name = "dist_files",
+    srcs = glob([
+        "google/**/*.proto",
+        "google/**/*.py",
+        "google/protobuf/internal/*.cc",
+        "google/protobuf/pyext/*.cc",
+        "google/protobuf/pyext/*.h",
+    ]) + [
+        "BUILD.bazel",
+        "MANIFEST.in",
+        "README.md",
+        "google/protobuf/proto_api.h",
+        "google/protobuf/pyext/README",
+        "google/protobuf/python_protobuf.h",
+        "internal.bzl",
+        "mox.py",
+        "release.sh",
+        "setup.cfg",
+        "setup.py",
+        "stubout.py",
+        "tox.ini",
+    ],
+    strip_prefix = strip_prefix.from_root(""),
+    visibility = ["//pkg:__pkg__"],
+)
diff --git a/python/internal.bzl b/python/internal.bzl
new file mode 100644
index 0000000000..a33a6a649e
--- /dev/null
+++ b/python/internal.bzl
@@ -0,0 +1,106 @@
+# Internal helpers for building the Python protobuf runtime.
+
+def _internal_copy_files_impl(ctx):
+    strip_prefix = ctx.attr.strip_prefix
+    if strip_prefix[-1] != "/":
+        strip_prefix += "/"
+
+    src_dests = []
+    for src in ctx.files.srcs:
+        if src.short_path[:len(strip_prefix)] != strip_prefix:
+            fail("Source does not start with %s: %s" %
+                 (strip_prefix, src.short_path))
+        dest = ctx.actions.declare_file(src.short_path[len(strip_prefix):])
+        src_dests.append([src, dest])
+
+    if ctx.attr.is_windows:
+        bat_file = ctx.actions.declare_file(ctx.label.name + "_copy.bat")
+        ctx.actions.write(
+            output = bat_file,
+            content = "\r\n".join([
+                '@copy /Y "{}" "{}" >NUL'.format(
+                    src.path.replace("/", "\\"),
+                    dest.path.replace("/", "\\"),
+                )
+                for src, dest in src_dests
+            ]) + "\r\n",
+        )
+        ctx.actions.run(
+            inputs = ctx.files.srcs,
+            tools = [bat_file],
+            outputs = [dest for src, dest in src_dests],
+            executable = "cmd.exe",
+            arguments = ["/C", bat_file.path.replace("/", "\\")],
+            mnemonic = "InternalCopyFile",
+            progress_message = "Copying files",
+            use_default_shell_env = True,
+        )
+
+    else:
+        sh_file = ctx.actions.declare_file(ctx.label.name + "_copy.sh")
+        ctx.actions.write(
+            output = sh_file,
+            content = "\n".join([
+                'cp -f "{}" "{}"'.format(src.path, dest.path)
+                for src, dest in src_dests
+            ]),
+        )
+        ctx.actions.run(
+            inputs = ctx.files.srcs,
+            tools = [sh_file],
+            outputs = [dest for src, dest in src_dests],
+            executable = "bash",
+            arguments = [sh_file.path],
+            mnemonic = "InternalCopyFile",
+            progress_message = "Copying files",
+            use_default_shell_env = True,
+        )
+
+    return [
+        DefaultInfo(files = depset([dest for src, dest in src_dests])),
+    ]
+
+internal_copy_files_impl = rule(
+    doc = """
+Implementation for internal_copy_files macro.
+
+This rule implements file copying, including a compatibility mode for Windows.
+""",
+    implementation = _internal_copy_files_impl,
+    attrs = {
+        "srcs": attr.label_list(allow_files = True, providers = [DefaultInfo]),
+        "strip_prefix": attr.string(),
+        "is_windows": attr.bool(),
+    },
+)
+
+def internal_copy_files(name, srcs, strip_prefix):
+    """Copies common proto files to the python tree.
+
+    In order for Python imports to work, generated proto interfaces under
+    the google.protobuf package need to be in the same directory as other
+    source files. This rule copies the .proto files themselves, e.g. with
+    strip_prefix = 'src', 'src/google/protobuf/blah.proto' could be copied
+    to '<package>/google/protobuf/blah.proto'.
+
+    (An alternative might be to implement a separate rule to generate
+    Python code in a different location for the sources. However, this
+    would be strange behavior that doesn't match any other language's proto
+    library generation.)
+
+    Args:
+      name: the name for the rule.
+      srcs: the sources.
+      strip_prefix: the prefix to remove from each of the paths in 'srcs'. The
+          remainder will be used to construct the output path.
+
+    """
+    internal_copy_files_impl(
+        name = name,
+        srcs = srcs,
+        strip_prefix = strip_prefix,
+        is_windows = select({
+            "@bazel_tools//src/conditions:host_windows": True,
+            "//conditions:default": False,
+        }),
+    )