diff --git a/src/EncoderProvider.php b/src/EncoderProvider.php
index 6b29688..4e98768 100644
--- a/src/EncoderProvider.php
+++ b/src/EncoderProvider.php
@@ -48,6 +48,7 @@ final class EncoderProvider implements ResetInterface
     ];
     private const MODEL_PREFIX_TO_ENCODING = [
         'o1-' => 'o200k_base',
+        'chatgpt-4o-' => 'o200k_base',
         'gpt-4o-' => 'o200k_base',
         'gpt-4-' => 'cl100k_base',
         'gpt-3.5-turbo-' => 'cl100k_base',