diff --git a/cpp/src/arrow/util/config.h.cmake b/cpp/src/arrow/util/config.h.cmake
index 692b1a2c88ea0..968c2e1898ebc 100644
--- a/cpp/src/arrow/util/config.h.cmake
+++ b/cpp/src/arrow/util/config.h.cmake
@@ -52,7 +52,7 @@
 #cmakedefine ARROW_SUBSTRAIT
 
 #cmakedefine ARROW_ENABLE_THREADING
-# TODO: Add Azure
+// TODO: Add Azure
 #cmakedefine ARROW_GCS
 #cmakedefine ARROW_S3
 #cmakedefine ARROW_USE_NATIVE_INT128