diff --git a/lib/telemetry_metrics.ex b/lib/telemetry_metrics.ex
index 9b63252..023d356 100644
--- a/lib/telemetry_metrics.ex
+++ b/lib/telemetry_metrics.ex
@@ -408,7 +408,7 @@ defmodule Telemetry.Metrics do
           | (:telemetry.event_measurements() -> number())
           | (:telemetry.event_measurements(), :telemetry.event_metadata() -> number())
   @type tag :: term()
-  @type tags :: [tag()]
+  @type tags :: [tag()] | :all
   @type tag_values :: (:telemetry.event_metadata() -> :telemetry.event_metadata())
   @type predicate_fun ::
           (:telemetry.event_metadata() -> boolean())
@@ -672,6 +672,8 @@ defmodule Telemetry.Metrics do
   end
 
   @spec validate_tags!(term()) :: :ok | no_return()
+  defp validate_tags!(:all), do: :ok
+
   defp validate_tags!(list) when is_list(list) do
     :ok
   end
diff --git a/test/telemetry_metrics_test.exs b/test/telemetry_metrics_test.exs
index 7fa993f..4843206 100644
--- a/test/telemetry_metrics_test.exs
+++ b/test/telemetry_metrics_test.exs
@@ -129,6 +129,16 @@ defmodule Telemetry.MetricsTest do
         assert event_metadata == tag_values_fun.(event_metadata)
       end
 
+      test "tags can use atom `:all` to mark that all metadata should be used" do
+        metric =
+          apply(Metrics, unquote(metric_type), [
+            "my.event.value",
+            [tags: :all]
+          ])
+
+        assert :all == metric.tags
+      end
+
       test "setting function as tag_values returns that function in metric spec" do
         metric =
           apply(Metrics, unquote(metric_type), [