diff --git a/code2schema/analyzer/events.py b/code2schema/analyzer/events.py
index 1a993f1..a985ec2 100644
--- a/code2schema/analyzer/events.py
+++ b/code2schema/analyzer/events.py
@@ -89,12 +89,14 @@ def _find_emitters(modules: List[ModuleIR]) -> List[DomainEvent]:
 
 def _find_handlers(events: List[DomainEvent], modules: List[ModuleIR]) -> None:
     """Krok 2: dopasuj handlery do zdarzeń (mutuje events in-place)."""
+    # Event keywords are invariant for this pass; normalize each only once.
+    keywords = [(ev, ev.name.lower().replace("event", "").strip()) for ev in events]
     for mod in modules:
         for f in mod.functions:
             if _EVENT_HANDLER_PATTERNS.search(f.name):
-                for ev in events:
-                    keyword = ev.name.lower().replace("event", "").strip()
-                    if keyword and keyword in f.name.lower():
+                handler_name = f.name.lower()
+                for ev, keyword in keywords:
+                    if keyword and keyword in handler_name:
                         ev.handled_by.append(f.qualified_name)
 
 
diff --git a/tests/test_event_handlers.py b/tests/test_event_handlers.py
new file mode 100644
index 0000000..415abc3
--- /dev/null
+++ b/tests/test_event_handlers.py
@@ -0,0 +1,30 @@
+import copy
+import re
+
+from code2schema.analyzer.events import DomainEvent, _find_handlers
+from code2schema.core.models import FunctionIR, ModuleIR
+
+
+def test_handler_matching_preserves_order_duplicates_case_and_empty_keywords():
+    names = ["UserEvent", "UserEvent", "Event", "Entity1Event", "Entity10Event", "ŻółćEvent"]
+    events = [DomainEvent(name=n, emitted_by=str(i), handled_by=["existing"]) for i,n in enumerate(names)]
+    modules = [ModuleIR(name=m, path=m+".py", functions=[FunctionIR(name=n,module=m) for n in [
+        "handle_user", "ON_USER", "handle_entity10", "on_żółć", "plain_user", "consumer_user"]]) for m in ["a","b"]]
+    expected = copy.deepcopy(events)
+    for _ in range(2):
+        for mod in modules:
+            for f in mod.functions:
+                if re.search(r"(on_|handle_|listener|subscriber|consumer|process_|receive_)", f.name, re.I):
+                    for ev in expected:
+                        keyword = ev.name.lower().replace("event", "").strip()
+                        if keyword and keyword in f.name.lower():
+                            ev.handled_by.append(f.qualified_name)
+        _find_handlers(events, modules)
+    assert events == expected
+
+
+def test_empty_events_and_modules_are_noops():
+    events = [DomainEvent(name="UserEvent", emitted_by="emit")]
+    _find_handlers(events, [])
+    _find_handlers([], [])
+    assert events[0].handled_by == []