diff --git a/sp/src/vscript/vscript_squirrel.cpp b/sp/src/vscript/vscript_squirrel.cpp
index 17d018cd..a16ac7a5 100644
--- a/sp/src/vscript/vscript_squirrel.cpp
+++ b/sp/src/vscript/vscript_squirrel.cpp
@@ -1071,7 +1071,7 @@ SQInteger IsValid_stub(HSQUIRRELVM vm)
 {
 	ClassInstanceData* classInstanceData = nullptr;
 	sq_getinstanceup(vm, 1, (SQUserPointer*)&classInstanceData, 0);
-	sq_pushbool(vm, classInstanceData == nullptr);
+	sq_pushbool(vm, classInstanceData != nullptr);
 	return 1;
 }
 
@@ -3034,4 +3034,4 @@ bool SquirrelVM::RaiseException(const char* pszExceptionText)
 IScriptVM* makeSquirrelVM()
 {
 	return new SquirrelVM;
-}
\ No newline at end of file
+}