diff --git a/tools/llvm-db/CLICommand.h b/tools/llvm-db/CLICommand.h
index 25451e747fc..ad8b8403bd3 100644
--- a/tools/llvm-db/CLICommand.h
+++ b/tools/llvm-db/CLICommand.h
@@ -17,6 +17,7 @@
 
 #include <string>
 #include <vector>
+#include <cassert>
 
 namespace llvm {
   class CLIDebugger;