diff --git a/BUILD b/BUILD
index f7136e4b846ad549435eb9d37e57865a60667af6..396e18d5a2da4e7137b4c1f8c03ad17113be5b6c 100644
--- a/BUILD
+++ b/BUILD
@@ -83,6 +83,7 @@ cc_library(
     "src/core/support/time.c",
     "src/core/support/time_posix.c",
     "src/core/support/time_win32.c",
+    "src/core/support/tls_pthread.c",
   ],
   hdrs = [
     "include/grpc/support/alloc.h",
diff --git a/Makefile b/Makefile
index fa954849100cca019b546b2ae70df7111dc842e0..32a2686f6ae683e166491f1909ce5352abfd8b01 100644
--- a/Makefile
+++ b/Makefile
@@ -2322,6 +2322,7 @@ LIBGPR_SRC = \
     src/core/support/time.c \
     src/core/support/time_posix.c \
     src/core/support/time_win32.c \
+    src/core/support/tls_pthread.c \
 
 PUBLIC_HEADERS_C += \
     include/grpc/support/alloc.h \
diff --git a/build.json b/build.json
index 39e61d2822a8f353133cf52f0a7cf7381b0daac7..18591d64f8255efd3d3e8f131cc435dcdd5ce7f3 100644
--- a/build.json
+++ b/build.json
@@ -370,7 +370,8 @@
         "src/core/support/thd_win32.c",
         "src/core/support/time.c",
         "src/core/support/time_posix.c",
-        "src/core/support/time_win32.c"
+        "src/core/support/time_win32.c",
+        "src/core/support/tls_pthread.c"
       ],
       "secure": "no",
       "vs_project_guid": "{B23D3D1A-9438-4EDA-BEB6-9A0A03D17792}"
diff --git a/include/grpc/support/tls_pthread.h b/include/grpc/support/tls_pthread.h
index 07eb12e5bf86d6a31ac0f9487588b8f0df8ae111..67f169dd7d3f7c455f5c9613077dbc46a82c48d0 100644
--- a/include/grpc/support/tls_pthread.h
+++ b/include/grpc/support/tls_pthread.h
@@ -34,6 +34,9 @@
 #ifndef GRPC_SUPPORT_TLS_PTHREAD_H
 #define GRPC_SUPPORT_TLS_PTHREAD_H
 
+#include <grpc/support/log.h>  /* for GPR_ASSERT */
+#include <pthread.h>
+
 /* Thread local storage based on pthread library calls.
    #include tls.h to use this - and see that file for documentation */
 
@@ -46,8 +49,7 @@ struct gpr_pthread_thread_local {
 
 #define gpr_tls_init(tls) GPR_ASSERT(0 == pthread_key_create(&(tls)->key, NULL))
 #define gpr_tls_destroy(tls) pthread_key_delete((tls)->key)
-#define gpr_tls_set(tls, new_value) \
-    (GPR_ASSERT(pthread_setspecific((tls)->key, (void*)(new_value)) == 0), (new_value))
+gpr_intptr gpr_tls_set(struct gpr_pthread_thread_local *tls, gpr_intptr value);
 #define gpr_tls_get(tls) ((gpr_intptr)pthread_getspecific((tls)->key))
 
 #endif
diff --git a/src/core/support/tls_pthread.c b/src/core/support/tls_pthread.c
new file mode 100644
index 0000000000000000000000000000000000000000..c3515e81cb737f87235b397719108a5926171f7d
--- /dev/null
+++ b/src/core/support/tls_pthread.c
@@ -0,0 +1,45 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+
+#ifdef GPR_PTHREAD_TLS
+
+#include <grpc/support/tls.h>
+
+gpr_intptr gpr_tls_set(struct gpr_pthread_thread_local *tls, gpr_intptr value) {
+  GPR_ASSERT(0 == pthread_set_specific(tls->key, (void*)value));
+  return value;
+}
+
+#endif /* GPR_PTHREAD_TLS */
diff --git a/vsprojects/gpr/gpr.vcxproj b/vsprojects/gpr/gpr.vcxproj
index e42c656fdcd54713ef270832f6910bf3ceeb9a88..6b81aaaf73bd1de7de8472c90e7f6524e8cbdd5e 100644
--- a/vsprojects/gpr/gpr.vcxproj
+++ b/vsprojects/gpr/gpr.vcxproj
@@ -252,6 +252,8 @@
     </ClCompile>
     <ClCompile Include="..\..\src\core\support\time_win32.c">
     </ClCompile>
+    <ClCompile Include="..\..\src\core\support\tls_pthread.c">
+    </ClCompile>
   </ItemGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">
diff --git a/vsprojects/gpr/gpr.vcxproj.filters b/vsprojects/gpr/gpr.vcxproj.filters
index 13fdb3fef84549df8a9da8b0b01db03702f757d2..41b30384a045f3fa956c06092795ba9d5bde4b69 100644
--- a/vsprojects/gpr/gpr.vcxproj.filters
+++ b/vsprojects/gpr/gpr.vcxproj.filters
@@ -106,6 +106,9 @@
     <ClCompile Include="..\..\src\core\support\time_win32.c">
       <Filter>src\core\support</Filter>
     </ClCompile>
+    <ClCompile Include="..\..\src\core\support\tls_pthread.c">
+      <Filter>src\core\support</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="..\..\include\grpc\support\alloc.h">