diff --git a/misc/factor.el b/misc/factor.el
index 9d90fb68f9..300c95c430 100644
--- a/misc/factor.el
+++ b/misc/factor.el
@@ -94,6 +94,10 @@
     "SYMBOLS:"
 ))
 
+(defun factor-indent-line ()
+  "Indent current line as Factor code"
+  (indent-line-to (+ (current-indentation) 4)))
+
 (defun factor-mode ()
   "A mode for editing programs written in the Factor programming language."
   (interactive)
@@ -107,6 +111,8 @@
   (setq font-lock-defaults
 	'(factor-font-lock-keywords nil nil nil nil))
   (set-syntax-table factor-mode-syntax-table)
+  (make-local-variable 'indent-line-function)
+  (setq indent-line-function 'factor-indent-line)
   (run-hooks 'factor-mode-hook))
 
 (add-to-list 'auto-mode-alist '("\\.factor\\'" . factor-mode))