diff --git a/include/grpc/support/avl.h b/include/grpc/support/avl.h
index d53ff5d9040..d8a5efd2ad5 100644
--- a/include/grpc/support/avl.h
+++ b/include/grpc/support/avl.h
@@ -21,6 +21,10 @@
 
 #include <grpc/support/sync.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /** internal node of an AVL tree */
 typedef struct gpr_avl_node {
   gpr_refcount refs;
@@ -91,4 +95,8 @@ GPRAPI int gpr_avl_maybe_get(gpr_avl avl, void *key, void **value,
 /** Return 1 if avl is empty, 0 otherwise */
 GPRAPI int gpr_avl_is_empty(gpr_avl avl);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_SUPPORT_AVL_H */
diff --git a/src/core/lib/iomgr/iomgr_uv.h b/src/core/lib/iomgr/iomgr_uv.h
index 3b4daaa73ba..bc42ca8c1c0 100644
--- a/src/core/lib/iomgr/iomgr_uv.h
+++ b/src/core/lib/iomgr/iomgr_uv.h
@@ -23,10 +23,18 @@
 
 #include <grpc/support/thd.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* The thread ID of the thread on which grpc was initialized. Used to verify
  * that all calls into libuv are made on that same thread */
 extern gpr_thd_id g_init_thread;
 
+#ifdef __cplusplus
+}
+#endif
+
 #ifdef GRPC_UV_THREAD_CHECK
 #define GRPC_UV_ASSERT_SAME_THREAD() \
   GPR_ASSERT(gpr_thd_currentid() == g_init_thread)
diff --git a/src/core/lib/iomgr/network_status_tracker.c b/src/core/lib/iomgr/network_status_tracker.c
index 4e5c1d5408c..fe5659160c1 100644
--- a/src/core/lib/iomgr/network_status_tracker.c
+++ b/src/core/lib/iomgr/network_status_tracker.c
@@ -17,6 +17,7 @@
  */
 
 #include "src/core/lib/iomgr/endpoint.h"
+#include "src/core/lib/iomgr/network_status_tracker.h"
 
 void grpc_network_status_shutdown(void) {}
 
diff --git a/src/core/lib/iomgr/wakeup_fd_cv.h b/src/core/lib/iomgr/wakeup_fd_cv.h
index 34bc42fd7f3..8f57de81523 100644
--- a/src/core/lib/iomgr/wakeup_fd_cv.h
+++ b/src/core/lib/iomgr/wakeup_fd_cv.h
@@ -66,8 +66,10 @@ typedef struct cv_fd_table {
   grpc_poll_function_type poll;
 } cv_fd_table;
 
+extern grpc_wakeup_fd_vtable grpc_cv_wakeup_fd_vtable;
+
 #ifdef __cplusplus
 }
 #endif
 
-#endif /* GRPC_CORE_LIB_IOMGR_WAKEUP_FD_CV_H */
\ No newline at end of file
+#endif /* GRPC_CORE_LIB_IOMGR_WAKEUP_FD_CV_H */
diff --git a/src/core/lib/iomgr/wakeup_fd_pipe.c b/src/core/lib/iomgr/wakeup_fd_pipe.c
index 4189488f8a3..c9c390b5872 100644
--- a/src/core/lib/iomgr/wakeup_fd_pipe.c
+++ b/src/core/lib/iomgr/wakeup_fd_pipe.c
@@ -21,6 +21,7 @@
 #ifdef GRPC_POSIX_WAKEUP_FD
 
 #include "src/core/lib/iomgr/wakeup_fd_posix.h"
+#include "src/core/lib/iomgr/wakeup_fd_pipe.h"
 
 #include <errno.h>
 #include <string.h>
diff --git a/src/core/lib/iomgr/wakeup_fd_pipe.h b/src/core/lib/iomgr/wakeup_fd_pipe.h
index f860406bda7..c4c95ab3580 100644
--- a/src/core/lib/iomgr/wakeup_fd_pipe.h
+++ b/src/core/lib/iomgr/wakeup_fd_pipe.h
@@ -21,6 +21,14 @@
 
 #include "src/core/lib/iomgr/wakeup_fd_posix.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 extern grpc_wakeup_fd_vtable grpc_pipe_wakeup_fd_vtable;
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_IOMGR_WAKEUP_FD_PIPE_H */
diff --git a/src/core/lib/iomgr/wakeup_fd_posix.c b/src/core/lib/iomgr/wakeup_fd_posix.c
index 25daa7d3fb7..9af96d314b5 100644
--- a/src/core/lib/iomgr/wakeup_fd_posix.c
+++ b/src/core/lib/iomgr/wakeup_fd_posix.c
@@ -25,7 +25,6 @@
 #include "src/core/lib/iomgr/wakeup_fd_pipe.h"
 #include "src/core/lib/iomgr/wakeup_fd_posix.h"
 
-extern grpc_wakeup_fd_vtable grpc_cv_wakeup_fd_vtable;
 static const grpc_wakeup_fd_vtable *wakeup_fd_vtable = NULL;
 
 int grpc_allow_specialized_wakeup_fd = 1;
diff --git a/src/core/lib/security/credentials/google_default/google_default_credentials.h b/src/core/lib/security/credentials/google_default/google_default_credentials.h
index c3755e01a6b..66677873caf 100644
--- a/src/core/lib/security/credentials/google_default/google_default_credentials.h
+++ b/src/core/lib/security/credentials/google_default/google_default_credentials.h
@@ -23,6 +23,10 @@
 
 #include "src/core/lib/security/credentials/credentials.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #define GRPC_GOOGLE_CLOUD_SDK_CONFIG_DIRECTORY "gcloud"
 #define GRPC_GOOGLE_WELL_KNOWN_CREDENTIALS_FILE \
   "application_default_credentials.json"
@@ -41,5 +45,9 @@
 
 void grpc_flush_cached_google_default_credentials(void);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_SECURITY_CREDENTIALS_GOOGLE_DEFAULT_GOOGLE_DEFAULT_CREDENTIALS_H \
           */
diff --git a/src/core/lib/security/transport/auth_filters.h b/src/core/lib/security/transport/auth_filters.h
index bd5902a128a..ba5df7fe70f 100644
--- a/src/core/lib/security/transport/auth_filters.h
+++ b/src/core/lib/security/transport/auth_filters.h
@@ -21,7 +21,15 @@
 
 #include "src/core/lib/channel/channel_stack.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 extern const grpc_channel_filter grpc_client_auth_filter;
 extern const grpc_channel_filter grpc_server_auth_filter;
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_SECURITY_TRANSPORT_AUTH_FILTERS_H */
diff --git a/src/core/lib/surface/alarm_internal.h b/src/core/lib/surface/alarm_internal.h
index 7f2126c5c91..136b60547fa 100644
--- a/src/core/lib/surface/alarm_internal.h
+++ b/src/core/lib/surface/alarm_internal.h
@@ -22,6 +22,10 @@
 #include <grpc/support/log.h>
 #include "src/core/lib/debug/trace.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #ifndef NDEBUG
 
 extern grpc_tracer_flag grpc_trace_alarm_refcount;
@@ -37,4 +41,8 @@ extern grpc_tracer_flag grpc_trace_alarm_refcount;
 
 #endif /* defined(NDEBUG) */
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_SURFACE_ALARM_INTERNAL_H */
diff --git a/src/core/lib/surface/api_trace.h b/src/core/lib/surface/api_trace.h
index 849cbaaef6e..105abdf629d 100644
--- a/src/core/lib/surface/api_trace.h
+++ b/src/core/lib/surface/api_trace.h
@@ -22,6 +22,10 @@
 #include <grpc/support/log.h>
 #include "src/core/lib/debug/trace.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 extern grpc_tracer_flag grpc_api_trace;
 
 /* Provide unwrapping macros because we're in C89 and variadic macros weren't
@@ -47,4 +51,8 @@ extern grpc_tracer_flag grpc_api_trace;
     gpr_log(GPR_INFO, fmt GRPC_API_TRACE_UNWRAP##nargs args); \
   }
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_SURFACE_API_TRACE_H */
diff --git a/src/core/lib/surface/lame_client.h b/src/core/lib/surface/lame_client.h
index 3ce353f101f..2f6f9cd046e 100644
--- a/src/core/lib/surface/lame_client.h
+++ b/src/core/lib/surface/lame_client.h
@@ -21,6 +21,14 @@
 
 #include "src/core/lib/channel/channel_stack.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 extern const grpc_channel_filter grpc_lame_filter;
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* GRPC_CORE_LIB_SURFACE_LAME_CLIENT_H */
diff --git a/src/core/lib/surface/validate_metadata.c b/src/core/lib/surface/validate_metadata.c
index 61209ae48d1..81d07fae442 100644
--- a/src/core/lib/surface/validate_metadata.c
+++ b/src/core/lib/surface/validate_metadata.c
@@ -26,6 +26,7 @@
 #include "src/core/lib/iomgr/error.h"
 #include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/slice/slice_string_helpers.h"
+#include "src/core/lib/surface/validate_metadata.h"
 
 static grpc_error *conforms_to(grpc_slice slice, const uint8_t *legal_bits,
                                const char *err_desc) {