diff --git a/docs/requirements-docs.txt b/docs/requirements-docs.txt
index 0e76763a..ed569816 100644
--- a/docs/requirements-docs.txt
+++ b/docs/requirements-docs.txt
@@ -10,3 +10,4 @@ pydantic
 torch
 py-cpuinfo
 transformers
+openai # Required by docs/source/serving/openai_compatible_server.md's vllm.entrypoints.openai.cli_args