diff --git a/lang/c/src/avro/refcount.h b/lang/c/src/avro/refcount.h
index 27369900ab9..fd431f3ccea 100644
--- a/lang/c/src/avro/refcount.h
+++ b/lang/c/src/avro/refcount.h
@@ -86,7 +86,10 @@ avro_refcount_dec(volatile int *refcount)
  * Mac OS X
  */
 
-#elif __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ >= 1050
+#elif __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ >= 1050 \
+  && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 101200
+
+/* macOS 10.12 deprecates OSAtomic* so we'll use the GCC/Clang branch below */
 
 #include <libkern/OSAtomic.h>