diff --git a/setup.py b/setup.py
index 5ac221ad46b..ccfda9d53d3 100644
--- a/setup.py
+++ b/setup.py
@@ -391,10 +391,7 @@ if "win32" in sys.platform:
         # on msvc, but only for 32 bits
         DEFINE_MACROS += (('NTDDI_VERSION', 0x06000000),)
 else:
-    DEFINE_MACROS += (
-        ('HAVE_CONFIG_H', 1),
-        ('GRPC_ENABLE_FORK_SUPPORT', 1),
-    )
+    DEFINE_MACROS += (('HAVE_CONFIG_H', 1),)
 
 LDFLAGS = tuple(EXTRA_LINK_ARGS)
 CFLAGS = tuple(EXTRA_COMPILE_ARGS)