diff --git a/nixos/modules/system/boot/grow-partition.nix b/nixos/modules/system/boot/grow-partition.nix
index a2764187a533..1ce4d5e56233 100644
--- a/nixos/modules/system/boot/grow-partition.nix
+++ b/nixos/modules/system/boot/grow-partition.nix
@@ -16,29 +16,28 @@ with lib;
   };
 
   config = mkIf config.boot.growPartition {
+    assertions = [
+      {
+        assertion = !config.boot.initrd.systemd.repart.enable && !config.systemd.repart.enable;
+        message = "systemd-repart already grows the root partition and thus you should not use boot.growPartition";
+      }
+    ];
+    systemd.services.growpart = {
+      wantedBy = [ "-.mount" ];
+      after = [ "-.mount" ];
+      before = [ "systemd-growfs-root.service" ];
+      conflicts = [ "shutdown.target" ];
+      unitConfig.DefaultDependencies = false;
+      serviceConfig = {
+        Type = "oneshot";
+        RemainAfterExit = true;
+        TimeoutSec = "infinity";
+        # growpart returns 1 if the partition is already grown
+        SuccessExitStatus = "0 1";
+      };
 
-    assertions = [{
-      assertion = !config.boot.initrd.systemd.enable;
-      message = "systemd stage 1 does not support 'boot.growPartition' yet.";
-    }];
-
-    boot.initrd.extraUtilsCommands = ''
-      copy_bin_and_libs ${pkgs.gawk}/bin/gawk
-      copy_bin_and_libs ${pkgs.gnused}/bin/sed
-      copy_bin_and_libs ${pkgs.util-linux}/sbin/sfdisk
-      copy_bin_and_libs ${pkgs.util-linux}/sbin/lsblk
-
-      substitute "${pkgs.cloud-utils.guest}/bin/.growpart-wrapped" "$out/bin/growpart" \
-        --replace "${pkgs.bash}/bin/sh" "/bin/sh" \
-        --replace "awk" "gawk" \
-        --replace "sed" "gnused"
-
-      ln -s sed $out/bin/gnused
-    '';
-
-    boot.initrd.postDeviceCommands = ''
-      rootDevice="${config.fileSystems."/".device}"
-      if waitDevice "$rootDevice"; then
+      script = ''
+        rootDevice="${config.fileSystems."/".device}"
         rootDevice="$(readlink -f "$rootDevice")"
         parentDevice="$rootDevice"
         while [ "''${parentDevice%[0-9]}" != "''${parentDevice}" ]; do
@@ -48,11 +47,8 @@ with lib;
         if [ "''${parentDevice%[0-9]p}" != "''${parentDevice}" ] && [ -b "''${parentDevice%p}" ]; then
           parentDevice="''${parentDevice%p}"
         fi
-        TMPDIR=/run sh $(type -P growpart) "$parentDevice" "$partNum"
-        udevadm settle
-      fi
-    '';
-
+        "${pkgs.cloud-utils.guest}/bin/growpart" "$parentDevice" "$partNum"
+      '';
+    };
   };
-
 }
diff --git a/nixos/tests/all-tests.nix b/nixos/tests/all-tests.nix
index 22371c9fec37..33f8abf6ccd4 100644
--- a/nixos/tests/all-tests.nix
+++ b/nixos/tests/all-tests.nix
@@ -332,6 +332,7 @@ in {
   graphite = handleTest ./graphite.nix {};
   graylog = handleTest ./graylog.nix {};
   grocy = handleTest ./grocy.nix {};
+  grow-partition = runTest ./grow-partition.nix;
   grub = handleTest ./grub.nix {};
   guacamole-server = handleTest ./guacamole-server.nix {};
   gvisor = handleTest ./gvisor.nix {};
diff --git a/nixos/tests/grow-partition.nix b/nixos/tests/grow-partition.nix
new file mode 100644
index 000000000000..344910848dca
--- /dev/null
+++ b/nixos/tests/grow-partition.nix
@@ -0,0 +1,83 @@
+{ lib, ... }:
+
+let
+  rootFslabel = "external";
+  rootFsDevice = "/dev/disk/by-label/${rootFslabel}";
+
+  externalModule = partitionTableType: { config, lib, pkgs, ... }: {
+    virtualisation.directBoot.enable = false;
+    virtualisation.mountHostNixStore = false;
+    virtualisation.useEFIBoot = partitionTableType == "efi";
+
+    # This stops the qemu-vm module from overriding the fileSystems option
+    # with virtualisation.fileSystems.
+    virtualisation.fileSystems = lib.mkForce { };
+
+
+    boot.loader.grub.enable = true;
+    boot.loader.grub.efiSupport = partitionTableType == "efi";
+    boot.loader.grub.efiInstallAsRemovable = partitionTableType == "efi";
+    boot.loader.grub.device = if partitionTableType == "efi" then "nodev" else "/dev/vda";
+
+    boot.growPartition = true;
+
+    fileSystems = {
+      "/".device = rootFsDevice;
+    };
+
+    system.build.diskImage = import ../lib/make-disk-image.nix {
+      inherit config lib pkgs;
+      label = rootFslabel;
+      inherit partitionTableType;
+      format = "raw";
+      bootSize = "128M";
+      additionalSpace = "0M";
+      copyChannel = false;
+    };
+  };
+in
+{
+  name = "grow-partition";
+
+  meta.maintainers = with lib.maintainers; [ arianvp ];
+
+  nodes = {
+    efi = externalModule "efi";
+    legacy = externalModule "legacy";
+    legacyGPT = externalModule "legacy+gpt";
+    hybrid = externalModule "hybrid";
+  };
+
+
+  testScript = { nodes, ... }:
+    lib.concatLines (lib.mapAttrsToList (name: node: ''
+    import os
+    import subprocess
+    import tempfile
+    import shutil
+
+    tmp_disk_image = tempfile.NamedTemporaryFile()
+
+    shutil.copyfile("${node.system.build.diskImage}/nixos.img", tmp_disk_image.name)
+
+    subprocess.run([
+      "${node.virtualisation.qemu.package}/bin/qemu-img",
+      "resize",
+      "-f",
+      "raw",
+      tmp_disk_image.name,
+      "+32M",
+    ])
+
+    # Set NIX_DISK_IMAGE so that the qemu script finds the right disk image.
+    os.environ['NIX_DISK_IMAGE'] = tmp_disk_image.name
+
+    ${name}.wait_for_unit("growpart.service")
+    systemd_growpart_logs = ${name}.succeed("journalctl --boot --unit growpart.service")
+    assert "CHANGED" in systemd_growpart_logs
+    ${name}.succeed("systemctl restart growpart.service")
+    systemd_growpart_logs = ${name}.succeed("journalctl --boot --unit growpart.service")
+    assert "NOCHANGE" in systemd_growpart_logs
+
+    '') nodes);
+}