diff --git a/lib/geo_postgis.ex b/lib/geo_postgis.ex
index 228ebff..66ae85f 100644
--- a/lib/geo_postgis.ex
+++ b/lib/geo_postgis.ex
@@ -401,6 +401,9 @@ defmodule Geo.PostGIS do
             )
   end
 
+  defmacro st_extent(geometry) do
+    quote do: fragment("ST_EXTENT(?)::geometry", unquote(geometry))
+
   defmacro st_build_area(geometryA) do
     quote do: fragment("ST_BuildArea(?)", unquote(geometryA))
   end
diff --git a/test/ecto_test.exs b/test/ecto_test.exs
index c64a536..b449197 100644
--- a/test/ecto_test.exs
+++ b/test/ecto_test.exs
@@ -123,6 +123,16 @@ defmodule Geo.Ecto.Test do
     assert results == 0
   end
 
+  test "st_extent" do
+    geom = Geo.WKB.decode!(@multipoint_wkb)
+
+    Repo.insert(%Location{name: "hello", geom: geom})
+
+    query = from(location in Location, select: st_extent(location.geom))
+    assert [%Geo.Polygon{coordinates: [coordinates]}] = Repo.all(query)
+    assert length(coordinates) == 5
+  end
+
   test "example" do
     geom = Geo.WKB.decode!(@multipoint_wkb)
     Repo.insert(%Location{name: "hello", geom: geom})