diff --git a/shell.nix b/shell.nix
index 921df98..b525a1a 100644
--- a/shell.nix
+++ b/shell.nix
@@ -50,7 +50,12 @@ in pkgs.mkShell {
         eval "$(${pkgs.nix}/bin/nix-build --no-out-link "${toString ./.}/deploy.nix" -A "$1")"
       '';
     in pkgs.writers.writeDashBin "niveum-deploy" ''
-      ${pkgs.parallel}/bin/parallel --line-buffer --tagstring '{}' -q ${deployCommand} '{1}' ::: "$@"
+      if [ -z "$(${pkgs.git}/bin/git status --porcelain)" ]; then
+        ${pkgs.parallel}/bin/parallel --line-buffer --tagstring '{}' -q ${deployCommand} '{1}' ::: "$@"
+      else
+        echo Working directory is dirty. Not deploying.
+        exit 1
+      fi
     '')
 
     (pkgs.writers.writeDashBin "niveum-status" ''