diff --git a/README.md b/README.md
index 69fa865..57f375f 100644
--- a/README.md
+++ b/README.md
@@ -320,6 +320,7 @@ Returns matching code chunks with:
 | javascript | js | `.js` |
 | json | | `.json` |
 | kotlin | | `.kt`, `.kts` |
+| lua | | `.lua` |
 | markdown | md | `.md`, `.mdx` |
 | pascal | pas, dpr, delphi | `.pas`, `.dpr` |
 | php | | `.php` |
diff --git a/src/cocoindex_code/indexer.py b/src/cocoindex_code/indexer.py
index 37b1f7f..1f93792 100644
--- a/src/cocoindex_code/indexer.py
+++ b/src/cocoindex_code/indexer.py
@@ -42,6 +42,7 @@
     "**/*.txt",  # Plain text
     "**/*.rst",  # reStructuredText
     "**/*.php",  # PHP
+    "**/*.lua",  # Lua
 ]
 
 INCLUDED_PATTERNS = DEFAULT_INCLUDED_PATTERNS + [f"**/*{ext}" for ext in config.extra_extensions]