diff --git a/saqc/flagger/baseflagger.py b/saqc/flagger/baseflagger.py
index ec91d77670aeb1e7782fb6056e4c9b9dffa86ff4..0eb4f8b9e3b3dd021cb809ce795c836ae4819bb0 100644
--- a/saqc/flagger/baseflagger.py
+++ b/saqc/flagger/baseflagger.py
@@ -14,6 +14,7 @@ from saqc.lib.tools import toSequence, assertScalar, assertDataFrame
 
 
 COMPARATOR_MAP = {
+    "!=": op.ne,
     "==": op.eq,
     ">=": op.ge,
     ">": op.gt,