diff --git a/django/contrib/gis/db/backends/postgis/base.py b/django/contrib/gis/db/backends/postgis/base.py
index 87a30004a1..98c2813aa2 100644
--- a/django/contrib/gis/db/backends/postgis/base.py
+++ b/django/contrib/gis/db/backends/postgis/base.py
@@ -23,4 +23,7 @@ class DatabaseWrapper(Psycopg2DatabaseWrapper):
         super().prepare_database()
         # Check that postgis extension is installed.
         with self.cursor() as cursor:
+            cursor.execute("SELECT 1 FROM pg_extension WHERE extname = %s", ["postgis"])
+            if bool(cursor.fetchone()):
+                return
             cursor.execute("CREATE EXTENSION IF NOT EXISTS postgis")