diff --git a/nixos/fish.nix b/nixos/fish.nix
index 7e34f22..10294ca 100644
--- a/nixos/fish.nix
+++ b/nixos/fish.nix
@@ -5,6 +5,7 @@
     enable = true;
     shellAliases = {
       cdtmp = "cd $(mktemp -d)";
+      gclean = "git cleanup-branches";
       theme = "bash ~/dotfiles/scripts/theme.sh";
       music = "mpv --no-video --log-file=~/music_history.log \"$(find $HOME/Music/ -type f \\( -name '*.mp3' -o -name '*.wav' -o -name '*.flac' -o -name '*.m4a' -o -name '*.ogg' \\) | fzf)\"";
       weather = "curl wttr.in/?T";
diff --git a/nixos/home/danny/home.nix b/nixos/home/danny/home.nix
index d14b454..b1d8345 100644
--- a/nixos/home/danny/home.nix
+++ b/nixos/home/danny/home.nix
@@ -74,6 +74,9 @@
       core = {
         editor = "nvim";
       };
+      alias = {
+        "cleanup-branches" = "!bash ~/dotfiles/scripts/git-cleanup-branches.sh";
+      };
     };
   };
 
diff --git a/scripts/git-cleanup-branches.sh b/scripts/git-cleanup-branches.sh
new file mode 100755
index 0000000..ef25f8c
--- /dev/null
+++ b/scripts/git-cleanup-branches.sh
@@ -0,0 +1,21 @@
+#!/usr/bin/env bash
+set -e
+
+git rev-parse --git-dir >/dev/null 2>&1 || { echo "Not a git repository." >&2; exit 1; }
+
+default_branch="main"
+git rev-parse --verify refs/heads/main &>/dev/null || default_branch="master"
+
+git branch --merged "$default_branch" \
+  | grep -Fv "$default_branch" \
+  | grep -vF '*' \
+  | grep -vF '+' \
+  | xargs git branch -d \
+  && git fetch \
+  && git remote prune origin \
+  && git branch -v \
+  | grep -F '[gone]' \
+  | grep -vF '*' \
+  | grep -vF '+' \
+  | awk '{print $1}' \
+  | xargs git branch -D