diff --git a/ftplugin/yaml.vim b/ftplugin/yaml.vim
new file mode 100644
index 0000000..ad695d7
--- /dev/null
+++ b/ftplugin/yaml.vim
@@ -0,0 +1,4 @@
+" Turn off syntax highlighting for large YAML files.
+if line('$') > 500
+  setlocal syntax=OFF
+endif