diff --git a/third-party/proxygen/CMakeLists.txt b/third-party/proxygen/CMakeLists.txt
index 3d91b633e0caa8..ae2f05a499fd0a 100644
--- a/third-party/proxygen/CMakeLists.txt
+++ b/third-party/proxygen/CMakeLists.txt
@@ -47,7 +47,7 @@ ExternalProject_Add(
     -DZSTD_INCLUDE_DIR=${ZSTD_INCLUDE_DIR}
     -DZSTD_LIBRARY_RELEASE=${ZSTD_LIBRARY}
 
-    "-DFizz_DIR=${FIZZ_INSTALL_DIR}/lib/cmake/fizz"
+    "-Dfizz_DIR=${FIZZ_INSTALL_DIR}/lib/cmake/fizz"
     "-Dfmt_DIR=${fmt_DIR}"
     "-Dfolly_DIR=${FOLLY_INSTALL_DIR}/lib/cmake/folly"
     "-Dwangle_DIR=${WANGLE_INSTALL_DIR}/lib/cmake/wangle"