diff --git a/superset/db_engine_specs/base.py b/superset/db_engine_specs/base.py
index 8db57e96c..36ac21961 100644
--- a/superset/db_engine_specs/base.py
+++ b/superset/db_engine_specs/base.py
@@ -1096,4 +1096,8 @@ class BaseEngineSpec:  # pylint: disable=too-many-public-methods
     @classmethod
     def is_readonly_query(cls, parsed_query: ParsedQuery) -> bool:
         """Pessimistic readonly, 100% sure statement won't mutate anything"""
-        return parsed_query.is_select() or parsed_query.is_explain()
+        return (
+            parsed_query.is_select()
+            or parsed_query.is_explain()
+            or parsed_query.is_show()
+        )
diff --git a/tests/db_engine_specs/base_engine_spec_tests.py b/tests/db_engine_specs/base_engine_spec_tests.py
index 57dd3cb2f..960a8d1c4 100644
--- a/tests/db_engine_specs/base_engine_spec_tests.py
+++ b/tests/db_engine_specs/base_engine_spec_tests.py
@@ -263,9 +263,11 @@ def test_is_readonly():
     def is_readonly(sql: str) -> bool:
         return BaseEngineSpec.is_readonly_query(ParsedQuery(sql))
 
-    assert not is_readonly("SHOW LOCKS test EXTENDED")
+    assert is_readonly("SHOW LOCKS test EXTENDED")
     assert not is_readonly("SET hivevar:desc='Legislators'")
     assert not is_readonly("UPDATE t1 SET col1 = NULL")
     assert is_readonly("EXPLAIN SELECT 1")
     assert is_readonly("SELECT 1")
     assert is_readonly("WITH (SELECT 1) bla SELECT * from bla")
+    assert is_readonly("SHOW CATALOGS")
+    assert is_readonly("SHOW TABLES")