diff --git a/flatpak-management.nix b/flatpak-management.nix
index 9925eb4..e9c01ac 100644
--- a/flatpak-management.nix
+++ b/flatpak-management.nix
@@ -32,7 +32,12 @@ let
     done
 
     # Hardcoded Threema install because the beta is not on Flathub yet
-    ${pkgs.flatpak}/bin/flatpak install -y --from https://releases.threema.ch/flatpak/threema-desktop/ch.threema.threema-desktop.flatpakref --noninteractive
+    if ${pkgs.flatpak}/bin/flatpak info ch.threema.threema-desktop >/dev/null 2>&1; then
+      echo "Threema Desktop is already installed"
+    else
+      echo "Installing Threema Desktop..."
+      ${pkgs.flatpak}/bin/flatpak install -y --from https://releases.threema.ch/flatpak/threema-desktop/ch.threema.threema-desktop.flatpakref --noninteractive
+    fi
 
     # Remove unused Flatpaks
     ${pkgs.flatpak}/bin/flatpak uninstall --unused -y --noninteractive