diff --git a/django/db/backends/ado_mssql/base.py b/django/db/backends/ado_mssql/base.py
index 8845f0f79b..8cc01862fd 100644
--- a/django/db/backends/ado_mssql/base.py
+++ b/django/db/backends/ado_mssql/base.py
@@ -90,7 +90,7 @@ class DatabaseWrapper(local):
 
 allows_group_by_ordinal = True
 allows_unique_and_pk = True
-autoindexes_primary_keys = False
+autoindexes_primary_keys = True
 needs_datetime_string_cast = True
 needs_upper_for_iops = False
 supports_constraints = True
diff --git a/django/db/backends/postgresql/base.py b/django/db/backends/postgresql/base.py
index 741d3a3c8c..3abd6d3a49 100644
--- a/django/db/backends/postgresql/base.py
+++ b/django/db/backends/postgresql/base.py
@@ -106,7 +106,7 @@ class DatabaseWrapper(local):
 
 allows_group_by_ordinal = True
 allows_unique_and_pk = True
-autoindexes_primary_keys = False
+autoindexes_primary_keys = True
 needs_datetime_string_cast = True
 needs_upper_for_iops = False
 supports_constraints = True
diff --git a/django/db/backends/postgresql_psycopg2/base.py b/django/db/backends/postgresql_psycopg2/base.py
index 22fcfeac67..9e846304ce 100644
--- a/django/db/backends/postgresql_psycopg2/base.py
+++ b/django/db/backends/postgresql_psycopg2/base.py
@@ -74,7 +74,7 @@ class DatabaseWrapper(local):
 
 allows_group_by_ordinal = True
 allows_unique_and_pk = True
-autoindexes_primary_keys = False
+autoindexes_primary_keys = True
 needs_datetime_string_cast = False
 needs_upper_for_iops = False
 supports_constraints = True
diff --git a/django/db/backends/sqlite3/base.py b/django/db/backends/sqlite3/base.py
index bd829f23a1..abd32a28d0 100644
--- a/django/db/backends/sqlite3/base.py
+++ b/django/db/backends/sqlite3/base.py
@@ -101,7 +101,7 @@ class SQLiteCursorWrapper(Database.Cursor):
 
 allows_group_by_ordinal = True
 allows_unique_and_pk = True
-autoindexes_primary_keys = False
+autoindexes_primary_keys = True
 needs_datetime_string_cast = True
 needs_upper_for_iops = False
 supports_constraints = False