diff --git a/floss/qs/main.py b/floss/qs/main.py
index 355c033e8..8cc2a542c 100644
--- a/floss/qs/main.py
+++ b/floss/qs/main.py
@@ -11,6 +11,7 @@
 import functools
 import itertools
 import contextlib
+from collections import defaultdict
 from typing import Set, Dict, List, Union, Tuple, Literal, Callable, Iterable, Optional, Sequence
 from dataclasses import field, dataclass
 
@@ -651,13 +652,21 @@ def tag_strings(self, taggers: Sequence[Tagger]):
         this can be overridden, if a subclass has more ways of tagging strings,
         such as a PE file and code/reloc regions.
         """
+        string_counts = defaultdict(int)
+        
         tagged_strings: List[TaggedString] = []
+
         for string in self.strings:
             # at this moment, the list of strings contains only ExtractedStrings.
             # this routine will transform them into TaggedStrings.
             assert isinstance(string, ExtractedString)
             tags: Set[Tag] = set()
 
+            string_counts[string.string] += 1
+
+            if string_counts[string.string] > 1:
+                tags.add("#duplicate")
+                
             for tagger in taggers:
                 tags.update(tagger(string))
 
@@ -1233,6 +1242,7 @@ def main():
     tag_rules: TagRules = {
         "#capa": "highlight",
         "#common": "mute",
+        "#duplicate": "mute",
         "#code": "hide",
         "#reloc": "hide",
         # lib strings are muted (default)