diff --git a/src/react/properties.py b/src/react/properties.py
index 398447fd..8e56158c 100644
--- a/src/react/properties.py
+++ b/src/react/properties.py
@@ -154,6 +154,9 @@ def __setitem__(self, key: _KT, item: _VT) -> None:
 
         super().__setitem__(key, item)
 
+        if item == old_value:
+            return
+
         self._notify_observers(key, old_value, item)
 
     def __delitem__(self, key: _KT) -> None: