diff --git a/stickerbridge/sticker_types.py b/stickerbridge/sticker_types.py
index 367e92c..e0c3a3d 100644
--- a/stickerbridge/sticker_types.py
+++ b/stickerbridge/sticker_types.py
@@ -15,6 +15,13 @@ class MatrixStickerset:
         }
 
     def add_sticker(self, mxc_uri: str, alt_text: str):
+        if alt_text in self._content['images']:
+            duplicate_counter = 1
+            alt_text = alt_text + '-' + str(duplicate_counter)
+            while (alt_text in self._content['images']):
+                duplicate_counter += 1
+                alt_text = alt_text.split('-')[0] + '-' + str(duplicate_counter)
+                print(alt_text)
         self._content['images'][alt_text] = {
             "url": mxc_uri,
             "usage": ["sticker"]