diff --git a/oni/packages/emacs-config.scm b/oni/packages/emacs-config.scm
index 0844ddb..98c112c 100644
--- a/oni/packages/emacs-config.scm
+++ b/oni/packages/emacs-config.scm
@@ -200,6 +200,7 @@ Emacs")))
       ("emacs-oni-lsp" ,emacs-oni-lsp)
       ("emacs-reformatter" ,emacs-reformatter)
       ("emacs-ccls" ,emacs-ccls)
+      ("emacs-rainbow-delimiters" ,emacs-rainbow-delimiters)
       ;; For `clang-format'.
       ("clang" ,clang)))
    (synopsis "My Emacs C coding configuration")