diff --git a/test/core/end2end/BUILD b/test/core/end2end/BUILD
index bb439fb18d210cb83ed007537e672d2a679a29bb..681cea1de74e1fce1ca37a8da493fc59533bcae2 100644
--- a/test/core/end2end/BUILD
+++ b/test/core/end2end/BUILD
@@ -34,6 +34,7 @@ cc_library(
   srcs = ['cq_verifier.c'],
   hdrs = ['cq_verifier.h'],
   deps = ['//:gpr', '//:grpc', '//test/core/util:grpc_test_util'],
+  copts = ['-std=c99'],
   visibility = ["//test:__subpackages__"],
 )
 
@@ -41,6 +42,7 @@ cc_library(
   name = 'ssl_test_data',
   visibility = ["//test:__subpackages__"],
   hdrs = ['data/ssl_test_data.h'],
+  copts = ['-std=c99'],
   srcs = [
     "data/client_certs.c",
     "data/server1_cert.c",
@@ -53,6 +55,7 @@ cc_library(
   name = 'fake_resolver',
   hdrs = ['fake_resolver.h'],
   srcs = ['fake_resolver.c'],
+  copts = ['-std=c99'],
   deps = ['//:gpr', '//:grpc', '//test/core/util:grpc_test_util']
 )
 
@@ -60,6 +63,7 @@ cc_library(
   name = 'http_proxy',
   hdrs = ['fixtures/http_proxy.h'],
   srcs = ['fixtures/http_proxy.c'],
+  copts = ['-std=c99'],
   deps = ['//:gpr', '//:grpc', '//test/core/util:grpc_test_util']
 )
 
@@ -67,6 +71,7 @@ cc_library(
   name = 'proxy',
   hdrs = ['fixtures/proxy.h'],
   srcs = ['fixtures/proxy.c'],
+  copts = ['-std=c99'],
   deps = ['//:gpr', '//:grpc', '//test/core/util:grpc_test_util']
 )
 
diff --git a/test/core/end2end/generate_tests.bzl b/test/core/end2end/generate_tests.bzl
index d6b0aaa2f4a349cccd2148fbf8fdb5c894a86194..aae8b4f7bdb6df98e8a3b1abef4547f2e16b4fc6 100755
--- a/test/core/end2end/generate_tests.bzl
+++ b/test/core/end2end/generate_tests.bzl
@@ -158,6 +158,7 @@ def grpc_end2end_tests():
       'tests/cancel_test_helpers.h',
       'end2end_tests.h'
     ],
+    copts = ['-std=c99'],
     deps = [
       ':cq_verifier',
       ':ssl_test_data',
@@ -175,6 +176,7 @@ def grpc_end2end_tests():
     native.cc_library(
       name = '%s_test_lib' % f,
       srcs = ['fixtures/%s.c' % f],
+      copts = ['-std=c99'],
       deps = [':end2end_tests']
     )
     for t, topt in END2END_TESTS.items():
@@ -183,5 +185,5 @@ def grpc_end2end_tests():
       native.cc_test(
         name = '%s_test@%s' % (f, t),
         args = [t],
-        deps = [':%s_test_lib' % f]
+        deps = [':%s_test_lib' % f],
       )