diff --git a/tests/test_simple_public.py b/tests/test_simple_public.py
index 8458c126..c6e67870 100644
--- a/tests/test_simple_public.py
+++ b/tests/test_simple_public.py
@@ -32,6 +32,16 @@ def test_encoding_for_model():
     enc = tiktoken.encoding_for_model("gpt-3.5-turbo-0301")
     assert enc.name == "cl100k_base"
 
+    # fine-tuned models
+    enc = tiktoken.encoding_for_model("davinci:ft-personal:finetunedmodel-2023-05-23-20-00-00")
+    assert enc.name == "r50k_base"
+    enc = tiktoken.encoding_for_model("curie:ft-personal:finetunedmodel-2023-05-23-20-00-00")
+    assert enc.name == "r50k_base"
+    enc = tiktoken.encoding_for_model("babbage:ft-personal:finetunedmodel-2023-05-23-20-00-00")
+    assert enc.name == "r50k_base"
+    enc = tiktoken.encoding_for_model("ada:ft-personal:finetunedmodel-2023-05-23-20-00-00")
+    assert enc.name == "r50k_base"
+
 
 def test_optional_blobfile_dependency():
     prog = """
diff --git a/tiktoken/model.py b/tiktoken/model.py
index 26201ce2..399df3bd 100644
--- a/tiktoken/model.py
+++ b/tiktoken/model.py
@@ -9,6 +9,11 @@
     "gpt-4-": "cl100k_base",  # e.g., gpt-4-0314, etc., plus gpt-4-32k
     "gpt-3.5-turbo-": "cl100k_base",  # e.g, gpt-3.5-turbo-0301, -0401, etc.
     "gpt-35-turbo": "cl100k_base",  # Azure deployment name
+    # fine-tuned models
+    "davinci": "r50k_base",
+    "curie": "r50k_base",
+    "babbage": "r50k_base",
+    "ada": "r50k_base",
 }
 
 MODEL_TO_ENCODING: dict[str, str] = {