diff --git a/oni-cmake.el b/oni-cmake.el
index 5524176..16968e6 100644
--- a/oni-cmake.el
+++ b/oni-cmake.el
@@ -4,7 +4,7 @@
 
 ;; Author: Tom Willemse <tom@ryuslash.org>
 ;; Keywords: local
-;; Version: 2021.0730.231115
+;; Version: 2022.0203.215032
 ;; Package-Requires: (cmake-mode oni-company oni-flycheck oni-lsp cmake-font-lock eldoc-cmake)
 
 ;; This program is free software; you can redistribute it and/or modify
@@ -26,6 +26,7 @@
 
 ;;; Code:
 
+(require 'cmake-mode)
 (require 'compile)
 (require 'flycheck)
 
@@ -34,6 +35,19 @@
   (setq-local comment-auto-fill-only-comments t)
   (auto-fill-mode))
 
+(defun oni-cmake-narrow-to-defun (&optional _include-comments)
+  "Narrow the current buffer the the function around point.
+_INCLUDE-COMMENTS is currently ignored."
+  (interactive)
+  (save-excursion
+    (let ((end (progn (cmake-end-of-defun)
+                      (point)))
+          (beginning (progn (cmake-beginning-of-defun)
+                            (point))))
+      (narrow-to-region beginning end))))
+
+(define-key cmake-mode-map (kbd "C-x n d") #'oni-cmake-narrow-to-defun)
+
 (add-hook 'cmake-mode-hook 'cmake-font-lock-activate)
 (add-hook 'cmake-mode-hook 'company-mode)
 (add-hook 'cmake-mode-hook 'display-fill-column-indicator-mode)