diff --git a/modules/major-modes/siren-prog-mode.el b/modules/major-modes/siren-prog-mode.el
index f166da2..230433a 100644
--- a/modules/major-modes/siren-prog-mode.el
+++ b/modules/major-modes/siren-prog-mode.el
@@ -21,7 +21,11 @@
     "Default coding hook, useful with any programming language."
     (setq-local fill-column 80)
 
-    (siren-display-indentation 1)
+    ;; Only show indentation if file size is below 100KB. It tends to cause a lot
+    ;; of lag and slowdowns on larger files, especially YAML files.
+    (if (< (buffer-size) (* 100 1024))
+        (siren-display-indentation 1))
+
     (hl-line-mode t)
     (visual-line-mode t)
     (whitespace-mode t)))