diff --git a/include/asterisk/lock.h b/include/asterisk/lock.h
index 055ec84c82..5f243915f6 100644
--- a/include/asterisk/lock.h
+++ b/include/asterisk/lock.h
@@ -114,6 +114,8 @@
 
 #define AST_MAX_REENTRANCY 10
 
+struct ast_channel;
+
 struct ast_mutex_info {
 	pthread_mutex_t mutex;
 	/*! Track which thread holds this lock */