diff --git a/pre_commit/clientlib.py b/pre_commit/clientlib.py
index 20d44925..916c5ff2 100644
--- a/pre_commit/clientlib.py
+++ b/pre_commit/clientlib.py
@@ -297,9 +297,13 @@ CONFIG_SCHEMA = cfgv.Map(
             'exclude',
             'fail_fast',
             'minimum_pre_commit_version',
+            'ci',
         ),
         warn_unknown_keys_root,
     ),
+
+    # do not warn about configuration for pre-commit.ci
+    cfgv.OptionalNoDefault('ci', cfgv.check_type(dict)),
 )
 
 
diff --git a/tests/clientlib_test.py b/tests/clientlib_test.py
index bfb754b6..ba602362 100644
--- a/tests/clientlib_test.py
+++ b/tests/clientlib_test.py
@@ -166,6 +166,20 @@ def test_validate_warn_on_unknown_keys_at_top_level(tmpdir, caplog):
     ]
 
 
+def test_ci_map_key_allowed_at_top_level(caplog):
+    cfg = {
+        'ci': {'skip': ['foo']},
+        'repos': [{'repo': 'meta', 'hooks': [{'id': 'identity'}]}],
+    }
+    cfgv.validate(cfg, CONFIG_SCHEMA)
+    assert not caplog.record_tuples
+
+
+def test_ci_key_must_be_map():
+    with pytest.raises(cfgv.ValidationError):
+        cfgv.validate({'ci': 'invalid', 'repos': []}, CONFIG_SCHEMA)
+
+
 def test_validate_optional_sensible_regex(caplog):
     config_obj = {
         'id': 'flake8',