diff --git a/src/thread.h b/src/thread.h
index b34ca3d57c8..82c445ba7e7 100644
--- a/src/thread.h
+++ b/src/thread.h
@@ -196,8 +196,6 @@ struct thread_state
   struct bc_thread_state bc;
 } GCALIGNED_STRUCT;
 
-INLINE_HEADER_BEGIN
-
 INLINE bool
 THREADP (Lisp_Object a)
 {