diff --git a/oni-core.el b/oni-core.el
index b18560b..cdc1a61 100644
--- a/oni-core.el
+++ b/oni-core.el
@@ -358,6 +358,11 @@ _s_: String list"
     (backward-char)
     (looking-back (rx word) (1- (point)))))
 
+(defun oni-core-ace-window-select-other-window ()
+  "Use ‘ace-window’ to select which window is considered “other”."
+  (interactive)
+  (setq other-window-scroll-buffer (ace-select-window)))
+
 (with-eval-after-load 'electric
   (add-hook 'electric-quote-inhibit-functions #'oni-core-in-word-p))
 
@@ -399,6 +404,7 @@ _s_: String list"
 
 (global-set-key (kbd "C-c w d") '("Delete a window" . ace-delete-window))
 (global-set-key (kbd "C-c w k") '("Keep a single window" . ace-delete-other-windows))
+(global-set-key (kbd "C-c w o") '("Select other window" . oni-core-ace-window-select-other-window))
 (global-set-key (kbd "M-g M") '("Jump to a mark anywhere" . consult-global-mark))
 (global-set-key (kbd "M-g m") '("Jump to a mark" . consult-mark))
 (global-set-key [remap bookmark-jump] 'consult-bookmark)