diff --git a/bazel/grpc_build_system.bzl b/bazel/grpc_build_system.bzl
index 08dc3de0ea8..3ec817748dc 100644
--- a/bazel/grpc_build_system.bzl
+++ b/bazel/grpc_build_system.bzl
@@ -108,7 +108,7 @@ def grpc_proto_library(name, srcs = [], deps = [], well_known_protos = False,
     generate_mocks = generate_mocks,
   )
 
-def grpc_cc_test(name, srcs = [], deps = [], external_deps = [], args = [], data = [], uses_polling = True, language = "C++"):
+def grpc_cc_test(name, srcs = [], deps = [], external_deps = [], args = [], data = [], uses_polling = True, language = "C++", size = "medium"):
   copts = []
   if language.upper() == "C":
     copts = if_not_windows(["-std=c99"])
@@ -120,6 +120,7 @@ def grpc_cc_test(name, srcs = [], deps = [], external_deps = [], args = [], data
     'deps': deps + _get_external_deps(external_deps),
     'copts': copts,
     'linkopts': if_not_windows(["-pthread"]),
+    'size': size,
   }
   if uses_polling:
     native.cc_test(testonly=True, tags=['manual'], **args)
diff --git a/test/core/util/grpc_fuzzer.bzl b/test/core/util/grpc_fuzzer.bzl
index cece023fc09..9847456067d 100644
--- a/test/core/util/grpc_fuzzer.bzl
+++ b/test/core/util/grpc_fuzzer.bzl
@@ -23,6 +23,7 @@ def grpc_fuzzer(name, corpus, srcs = [], deps = [], **kwargs):
     external_deps = [
       'gtest',
     ],
+    size = "enormous",
     args = ["--directory=" + native.package_name() + "/" + corpus,],
     **kwargs
   )
diff --git a/tools/internal_ci/linux/grpc_asan_on_foundry.sh b/tools/internal_ci/linux/grpc_asan_on_foundry.sh
index 2f9c8531a07..2aebb65552e 100644
--- a/tools/internal_ci/linux/grpc_asan_on_foundry.sh
+++ b/tools/internal_ci/linux/grpc_asan_on_foundry.sh
@@ -13,6 +13,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-EXTRA_FLAGS="--copt=-gmlt --strip=never --copt=-fsanitize=address --linkopt=-fsanitize=address"
+EXTRA_FLAGS="--copt=-gmlt --strip=never --copt=-fsanitize=address --linkopt=-fsanitize=address --test_timeout=3600"
 github/grpc/tools/internal_ci/linux/grpc_bazel_on_foundry_base.sh "${EXTRA_FLAGS}"
 
diff --git a/tools/internal_ci/linux/grpc_bazel_on_foundry_base.sh b/tools/internal_ci/linux/grpc_bazel_on_foundry_base.sh
index a202aafb507..7ec15bf2567 100755
--- a/tools/internal_ci/linux/grpc_bazel_on_foundry_base.sh
+++ b/tools/internal_ci/linux/grpc_bazel_on_foundry_base.sh
@@ -38,7 +38,6 @@ source tools/internal_ci/helper_scripts/prepare_build_linux_rc
 "${KOKORO_GFILE_DIR}/bazel_wrapper.py" \
   --host_jvm_args=-Dbazel.DigestFunction=SHA256 \
   test --jobs="100" \
-  --test_timeout="3600,3600,3600,3600" \
   --test_output=errors  \
   --verbose_failures=true  \
   --keep_going  \
diff --git a/tools/internal_ci/linux/grpc_bazel_on_foundry_dbg.sh b/tools/internal_ci/linux/grpc_bazel_on_foundry_dbg.sh
index e5ffea62595..f5111e2febe 100644
--- a/tools/internal_ci/linux/grpc_bazel_on_foundry_dbg.sh
+++ b/tools/internal_ci/linux/grpc_bazel_on_foundry_dbg.sh
@@ -13,6 +13,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-EXTRA_FLAGS="-c dbg"
+EXTRA_FLAGS="-c dbg --test_timeout=300,450,1200,7200"
 github/grpc/tools/internal_ci/linux/grpc_bazel_on_foundry_base.sh "${EXTRA_FLAGS}"
 
diff --git a/tools/internal_ci/linux/grpc_bazel_on_foundry_opt.sh b/tools/internal_ci/linux/grpc_bazel_on_foundry_opt.sh
index 6a769b9a7c3..7f3e4cf8b53 100644
--- a/tools/internal_ci/linux/grpc_bazel_on_foundry_opt.sh
+++ b/tools/internal_ci/linux/grpc_bazel_on_foundry_opt.sh
@@ -13,5 +13,5 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-EXTRA_FLAGS="-c opt"
+EXTRA_FLAGS="-c opt --test_timeout=300,450,1200,7200"
 github/grpc/tools/internal_ci/linux/grpc_bazel_on_foundry_base.sh "${EXTRA_FLAGS}"
diff --git a/tools/internal_ci/linux/grpc_tsan_on_foundry.sh b/tools/internal_ci/linux/grpc_tsan_on_foundry.sh
index f8e665ba8a4..aacb1ad4969 100644
--- a/tools/internal_ci/linux/grpc_tsan_on_foundry.sh
+++ b/tools/internal_ci/linux/grpc_tsan_on_foundry.sh
@@ -13,6 +13,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-EXTRA_FLAGS="--copt=-gmlt --strip=never --copt=-fsanitize=thread --linkopt=-fsanitize=thread"
+EXTRA_FLAGS="--copt=-gmlt --strip=never --copt=-fsanitize=thread --linkopt=-fsanitize=thread --test_timeout=3600"
 github/grpc/tools/internal_ci/linux/grpc_bazel_on_foundry_base.sh "${EXTRA_FLAGS}"