diff --git a/lib/mox.ex b/lib/mox.ex
index 27e034b..22f0001 100644
--- a/lib/mox.ex
+++ b/lib/mox.ex
@@ -780,9 +780,11 @@ defmodule Mox do
   @spec verify_on_exit!(term()) :: :ok
   def verify_on_exit!(_context \\ %{}) do
     pid = self()
+    NimbleOwnership.set_owner_to_manual_cleanup(@this, pid)
 
     ExUnit.Callbacks.on_exit(Mox, fn ->
-      verify_mock_or_all!(pid, :all)
+      __verify_mock_or_all__(pid, :all)
+      NimbleOwnership.cleanup_owner(@this, pid)
     end)
   end
 
@@ -792,7 +794,7 @@ defmodule Mox do
   """
   @spec verify!() :: :ok
   def verify! do
-    verify_mock_or_all!(self(), :all)
+    __verify_mock_or_all__(self(), :all)
   end
 
   @doc """
@@ -801,10 +803,12 @@ defmodule Mox do
   @spec verify!(t()) :: :ok
   def verify!(mock) do
     validate_mock!(mock)
-    verify_mock_or_all!(self(), mock)
+    __verify_mock_or_all__(self(), mock)
   end
 
-  defp verify_mock_or_all!(owner_pid, mock_or_all) do
+  # Made public for testing.
+  @doc false
+  def __verify_mock_or_all__(owner_pid, mock_or_all) do
     all_expectations = NimbleOwnership.get_owned(@this, owner_pid, _default = %{}, @timeout)
 
     pending =
diff --git a/mix.exs b/mix.exs
index f01b98b..9ae6e5a 100644
--- a/mix.exs
+++ b/mix.exs
@@ -30,7 +30,7 @@ defmodule Mox.MixProject do
 
   defp deps do
     [
-      {:nimble_ownership, "~> 0.2.0"},
+      {:nimble_ownership, "~> 0.3.0"},
       {:ex_doc, "~> 0.16", only: :docs}
     ]
   end
diff --git a/mix.lock b/mix.lock
index ddb068c..36d7fbb 100644
--- a/mix.lock
+++ b/mix.lock
@@ -4,6 +4,6 @@
   "makeup": {:hex, :makeup, "1.1.0", "6b67c8bc2882a6b6a445859952a602afc1a41c2e08379ca057c0f525366fc3ca", [:mix], [{:nimble_parsec, "~> 1.2.2 or ~> 1.3", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "0a45ed501f4a8897f580eabf99a2e5234ea3e75a4373c8a52824f6e873be57a6"},
   "makeup_elixir": {:hex, :makeup_elixir, "0.16.0", "f8c570a0d33f8039513fbccaf7108c5d750f47d8defd44088371191b76492b0b", [:mix], [{:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: false]}, {:nimble_parsec, "~> 1.2.3", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "28b2cbdc13960a46ae9a8858c4bebdec3c9a6d7b4b9e7f4ed1502f8159f338e7"},
   "makeup_erlang": {:hex, :makeup_erlang, "0.1.1", "3fcb7f09eb9d98dc4d208f49cc955a34218fc41ff6b84df7c75b3e6e533cc65f", [:mix], [{:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: false]}], "hexpm", "174d0809e98a4ef0b3309256cbf97101c6ec01c4ab0b23e926a9e17df2077cbb"},
-  "nimble_ownership": {:hex, :nimble_ownership, "0.2.0", "5f09a97ce97a873945be4fe52c583f5649954109e7290b11809d7e3271222f96", [:mix], [], "hexpm", "81fa952d95717ca7ee55231f01374078464436aeab49a848121e5602e84cd97e"},
+  "nimble_ownership": {:hex, :nimble_ownership, "0.3.0", "29514f8779b26f50f9c07109677c98c0cc0b8025e89f82964dafa9cf7d657ec0", [:mix], [], "hexpm", "76c605106bc1e60f5b028b20203a1e0c90b4350b08e4b8a33f68bb50dcb6e837"},
   "nimble_parsec": {:hex, :nimble_parsec, "1.2.3", "244836e6e3f1200c7f30cb56733fd808744eca61fd182f731eac4af635cc6d0b", [:mix], [], "hexpm", "c8d789e39b9131acf7b99291e93dae60ab48ef14a7ee9d58c6964f59efb570b0"},
 }
diff --git a/test/mox_test.exs b/test/mox_test.exs
index 906f2bd..aa88a84 100644
--- a/test/mox_test.exs
+++ b/test/mox_test.exs
@@ -638,6 +638,26 @@ defmodule MoxTest do
 
       Task.await(task)
     end
+
+    test "raises if the mocks are not called" do
+      pid = self()
+
+      verify_on_exit!()
+
+      # This replicates exactly what verify_on_exit/1 does, but it adds an assertion
+      # in there. There's no easy way to test that something gets raised in an on_exit
+      # callback.
+      ExUnit.Callbacks.on_exit(Mox, fn ->
+        assert_raise Mox.VerificationError, fn ->
+          Mox.__verify_mock_or_all__(pid, :all)
+          NimbleOwnership.cleanup_owner({:global, Mox.Server}, pid)
+        end
+      end)
+
+      set_mox_private()
+
+      expect(CalcMock, :add, fn x, y -> x + y end)
+    end
   end
 
   describe "stub/3" do