diff --git a/loopy/kernel/__init__.py b/loopy/kernel/__init__.py
index 8275c8678d3cb86fd5ab7a8cf44485cb056b1b4c..46888e620501785073e2abf58180a5c6c93109d1 100644
--- a/loopy/kernel/__init__.py
+++ b/loopy/kernel/__init__.py
@@ -1206,6 +1206,9 @@ class LoopKernel(RecordWithoutPickling):
 
         for field_name in self.comparison_fields:
             if field_name == "domains":
+                if len(self.domains) != len(other.domains):
+                    return False
+
                 for set_a, set_b in zip(self.domains, other.domains):
                     if not set_a.plain_is_equal(set_b):
                         return False