diff --git a/test/core/client_channel/uri_fuzzer_test.cc b/test/core/client_channel/uri_fuzzer_test.cc
index f76c41d4372..ba31793ff3b 100644
--- a/test/core/client_channel/uri_fuzzer_test.cc
+++ b/test/core/client_channel/uri_fuzzer_test.cc
@@ -28,7 +28,7 @@
 bool squelch = true;
 bool leak_check = true;
 
-int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   char* s = static_cast<char*>(gpr_malloc(size + 1));
   memcpy(s, data, size);
   s[size] = 0;
diff --git a/test/core/end2end/fuzzers/api_fuzzer.cc b/test/core/end2end/fuzzers/api_fuzzer.cc
index 39e18dd121a..0b49b89205a 100644
--- a/test/core/end2end/fuzzers/api_fuzzer.cc
+++ b/test/core/end2end/fuzzers/api_fuzzer.cc
@@ -740,7 +740,7 @@ static validator* make_finished_batch_validator(call_state* cs,
   return create_validator(finished_batch, bi);
 }
 
-int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   grpc_test_only_set_slice_hash_seed(0);
   char* grpc_trace_fuzzer = gpr_getenv("GRPC_TRACE_FUZZER");
   if (squelch && grpc_trace_fuzzer == nullptr) gpr_set_log_function(dont_log);
diff --git a/test/core/end2end/fuzzers/client_fuzzer.cc b/test/core/end2end/fuzzers/client_fuzzer.cc
index 89edaa5ec0f..ebc8c2780d2 100644
--- a/test/core/end2end/fuzzers/client_fuzzer.cc
+++ b/test/core/end2end/fuzzers/client_fuzzer.cc
@@ -37,7 +37,7 @@ static void* tag(int n) { return (void*)(uintptr_t)n; }
 
 static void dont_log(gpr_log_func_args* args) {}
 
-int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   grpc_test_only_set_slice_hash_seed(0);
   struct grpc_memory_counters counters;
   if (squelch) gpr_set_log_function(dont_log);
diff --git a/test/core/end2end/fuzzers/server_fuzzer.cc b/test/core/end2end/fuzzers/server_fuzzer.cc
index b0221294dd4..fb6477b5798 100644
--- a/test/core/end2end/fuzzers/server_fuzzer.cc
+++ b/test/core/end2end/fuzzers/server_fuzzer.cc
@@ -35,7 +35,7 @@ static int detag(void* p) { return (int)(uintptr_t)p; }
 
 static void dont_log(gpr_log_func_args* args) {}
 
-int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   grpc_test_only_set_slice_hash_seed(0);
   struct grpc_memory_counters counters;
   if (squelch) gpr_set_log_function(dont_log);
diff --git a/test/core/http/request_fuzzer.cc b/test/core/http/request_fuzzer.cc
index 73f366cd9aa..368ac1b49db 100644
--- a/test/core/http/request_fuzzer.cc
+++ b/test/core/http/request_fuzzer.cc
@@ -27,7 +27,7 @@
 bool squelch = true;
 bool leak_check = true;
 
-int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   grpc_http_parser parser;
   grpc_http_request request;
   memset(&request, 0, sizeof(request));
diff --git a/test/core/http/response_fuzzer.cc b/test/core/http/response_fuzzer.cc
index 6c1fea50ae8..2a793fddd4b 100644
--- a/test/core/http/response_fuzzer.cc
+++ b/test/core/http/response_fuzzer.cc
@@ -26,7 +26,7 @@
 bool squelch = true;
 bool leak_check = true;
 
-int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   grpc_http_parser parser;
   grpc_http_response response;
   memset(&response, 0, sizeof(response));
diff --git a/test/core/json/fuzzer.cc b/test/core/json/fuzzer.cc
index fd9172ffba6..6dafabb95b3 100644
--- a/test/core/json/fuzzer.cc
+++ b/test/core/json/fuzzer.cc
@@ -29,7 +29,7 @@
 bool squelch = true;
 bool leak_check = true;
 
-int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   char* s;
   struct grpc_memory_counters counters;
   grpc_memory_counters_init();
diff --git a/test/core/nanopb/fuzzer_response.cc b/test/core/nanopb/fuzzer_response.cc
index 42826c18f3c..7039c801cb9 100644
--- a/test/core/nanopb/fuzzer_response.cc
+++ b/test/core/nanopb/fuzzer_response.cc
@@ -28,7 +28,7 @@ bool leak_check = true;
 
 static void dont_log(gpr_log_func_args* args) {}
 
-int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   if (squelch) gpr_set_log_function(dont_log);
   grpc_slice slice = grpc_slice_from_copied_buffer((const char*)data, size);
   grpc_grpclb_initial_response* response;
diff --git a/test/core/nanopb/fuzzer_serverlist.cc b/test/core/nanopb/fuzzer_serverlist.cc
index 059e33d584b..0a6b1767a1a 100644
--- a/test/core/nanopb/fuzzer_serverlist.cc
+++ b/test/core/nanopb/fuzzer_serverlist.cc
@@ -28,7 +28,7 @@ bool leak_check = true;
 
 static void dont_log(gpr_log_func_args* args) {}
 
-int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   if (squelch) gpr_set_log_function(dont_log);
   grpc_slice slice = grpc_slice_from_copied_buffer((const char*)data, size);
   grpc_grpclb_serverlist* serverlist;
diff --git a/test/core/security/ssl_server_fuzzer.cc b/test/core/security/ssl_server_fuzzer.cc
index a2d0f14de05..bbb2f6013ee 100644
--- a/test/core/security/ssl_server_fuzzer.cc
+++ b/test/core/security/ssl_server_fuzzer.cc
@@ -51,7 +51,7 @@ static void on_handshake_done(grpc_exec_ctx* exec_ctx, void* arg,
   GPR_ASSERT(error != GRPC_ERROR_NONE);
 }
 
-int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   struct grpc_memory_counters counters;
   if (squelch) gpr_set_log_function(dont_log);
   if (leak_check) grpc_memory_counters_init();
diff --git a/test/core/slice/percent_decode_fuzzer.cc b/test/core/slice/percent_decode_fuzzer.cc
index e6458736d39..3603177c47f 100644
--- a/test/core/slice/percent_decode_fuzzer.cc
+++ b/test/core/slice/percent_decode_fuzzer.cc
@@ -29,7 +29,7 @@
 bool squelch = true;
 bool leak_check = true;
 
-int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   struct grpc_memory_counters counters;
   grpc_memory_counters_init();
   grpc_slice input = grpc_slice_from_copied_buffer((const char*)data, size);
diff --git a/test/core/slice/percent_encode_fuzzer.cc b/test/core/slice/percent_encode_fuzzer.cc
index 776a998e51c..c8e3849fc8e 100644
--- a/test/core/slice/percent_encode_fuzzer.cc
+++ b/test/core/slice/percent_encode_fuzzer.cc
@@ -51,7 +51,7 @@ static void test(const uint8_t* data, size_t size, const uint8_t* dict) {
   GPR_ASSERT(counters.total_size_relative == 0);
 }
 
-int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   test(data, size, grpc_url_percent_encoding_unreserved_bytes);
   test(data, size, grpc_compatible_percent_encoding_unreserved_bytes);
   return 0;
diff --git a/test/core/transport/chttp2/hpack_parser_fuzzer_test.cc b/test/core/transport/chttp2/hpack_parser_fuzzer_test.cc
index 01230eb6759..942f25e0b75 100644
--- a/test/core/transport/chttp2/hpack_parser_fuzzer_test.cc
+++ b/test/core/transport/chttp2/hpack_parser_fuzzer_test.cc
@@ -34,7 +34,7 @@ static void onhdr(grpc_exec_ctx* exec_ctx, void* ud, grpc_mdelem md) {
 }
 static void dont_log(gpr_log_func_args* args) {}
 
-int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   grpc_test_only_set_slice_hash_seed(0);
   if (squelch) gpr_set_log_function(dont_log);
   grpc_init();
diff --git a/test/core/util/fuzzer_corpus_test.cc b/test/core/util/fuzzer_corpus_test.cc
index e2ed301c942..7849321257d 100644
--- a/test/core/util/fuzzer_corpus_test.cc
+++ b/test/core/util/fuzzer_corpus_test.cc
@@ -28,7 +28,7 @@
 #include "src/core/lib/iomgr/load_file.h"
 #include "test/core/util/test_config.h"
 
-int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size);
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size);
 extern bool squelch;
 extern bool leak_check;
 
diff --git a/test/core/util/one_corpus_entry_fuzzer.cc b/test/core/util/one_corpus_entry_fuzzer.cc
index a5512636f72..c0b67da1e26 100644
--- a/test/core/util/one_corpus_entry_fuzzer.cc
+++ b/test/core/util/one_corpus_entry_fuzzer.cc
@@ -21,7 +21,7 @@
 #include <grpc/support/log.h>
 #include "src/core/lib/iomgr/load_file.h"
 
-int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size);
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size);
 
 extern bool squelch;
 extern bool leak_check;