diff --git a/test/core/transport/chttp2/BUILD b/test/core/transport/chttp2/BUILD
index 62ebee2559e..36caec60b28 100644
--- a/test/core/transport/chttp2/BUILD
+++ b/test/core/transport/chttp2/BUILD
@@ -225,6 +225,7 @@ grpc_cc_test(
     timeout = "long",  # Required for internal test infrastructure (cl/325757166)
     srcs = ["too_many_pings_test.cc"],
     external_deps = ["gtest"],
+    shard_count = 7,
     deps = [
         "//:gpr",
         "//:grpc",
diff --git a/test/cpp/end2end/xds/BUILD b/test/cpp/end2end/xds/BUILD
index 3c3cefef540..e9637b7e1f2 100644
--- a/test/cpp/end2end/xds/BUILD
+++ b/test/cpp/end2end/xds/BUILD
@@ -155,7 +155,7 @@ grpc_cc_test(
     ],
     flaky = True,  # TODO(b/144705388)
     linkstatic = True,  # Fixes dyld error on MacOS
-    shard_count = 10,
+    shard_count = 20,
     tags = [
         "no_test_ios",
         "no_windows",
@@ -203,6 +203,7 @@ grpc_cc_test(
         "gtest",
     ],
     linkstatic = True,  # Fixes dyld error on MacOS
+    shard_count = 15,
     tags = [
         "no_test_ios",
         "no_windows",
@@ -250,6 +251,7 @@ grpc_cc_test(
         "gtest",
     ],
     linkstatic = True,  # Fixes dyld error on MacOS
+    shard_count = 5,
     tags = [
         "no_test_ios",
         "no_windows",
@@ -300,6 +302,7 @@ grpc_cc_test(
     ],
     flaky = True,  # TODO(b/144705388)
     linkstatic = True,  # Fixes dyld error on MacOS
+    shard_count = 10,
     tags = [
         "no_test_ios",
         "no_windows",