diff --git a/convert_hf_to_gguf.py b/convert_hf_to_gguf.py
index a9c40c8c..fb683d36 100644
--- a/convert_hf_to_gguf.py
+++ b/convert_hf_to_gguf.py
@@ -715,6 +715,9 @@ class Model:
         if chkhsh == "9dcf830ee9990cdbf78cc523a5f7bd9ad8f3f9890c2d3581d2785ad10f07049d":
             # ref: https://huggingface.co/JetBrains/Mellum2-12B-A2.5B-Base
             res = "mellum2"
+        if chkhsh == "ccc2ef013c104be7bae2965776d611e1d7a8a2a9c547dd93a682c9a9fc80352e":
+            # ref: https://huggingface.co/openai/gpt-oss-20b
+            res = "gpt-4o"
         if res is None:
             logger.warning("\n")
             logger.warning("**************************************************************************************")
diff --git a/convert_hf_to_gguf_update.py b/convert_hf_to_gguf_update.py
index 9168f903..0c9b6dfd 100755
--- a/convert_hf_to_gguf_update.py
+++ b/convert_hf_to_gguf_update.py
@@ -106,6 +106,7 @@ models = [
     {"name": "grok-2",         "tokt": TOKENIZER_TYPE.BPE, "repo": "https://huggingface.co/alvarobartt/grok-2-tokenizer", "chkhsh": "66b8d4e19ab16c3bfd89bce5d785fb7e0155e8648708a1f42077cb9fe002c273"},
     {"name": "minimax-m2",     "tokt": TOKENIZER_TYPE.BPE, "repo": "https://huggingface.co/MiniMaxAI/MiniMax-M2", },
     {"name": "mellum2",        "tokt": TOKENIZER_TYPE.BPE, "repo": "https://huggingface.co/JetBrains/Mellum2-12B-A2.5B-Base", },
+    {"name": "gpt-4o",         "tokt": TOKENIZER_TYPE.BPE, "repo": "https://huggingface.co/openai/gpt-oss-20b", "chkhsh": "ccc2ef013c104be7bae2965776d611e1d7a8a2a9c547dd93a682c9a9fc80352e", },  # o200k_harmony shares the GPT-4o pre-tokenizer
 ]