diff --git a/tests/test_cli.py b/tests/test_cli.py
index 3ac5b09..7d16412 100644
--- a/tests/test_cli.py
+++ b/tests/test_cli.py
@@ -29,7 +29,7 @@ from yamllint import cli
 from yamllint import config
 
 
-class RunContext(object):
+class RunContext:
     """Context manager for ``cli.run()`` to capture exit code and streams."""
 
     def __init__(self, case):
diff --git a/tests/test_config.py b/tests/test_config.py
index 3618a30..c84be1e 100644
--- a/tests/test_config.py
+++ b/tests/test_config.py
@@ -121,7 +121,7 @@ class SimpleConfigTestCase(unittest.TestCase):
         self.assertEqual(c.rules['hyphens'], False)
 
     def test_validate_rule_conf(self):
-        class Rule(object):
+        class Rule:
             ID = 'fake'
 
         self.assertFalse(config.validate_rule_conf(Rule, False))
diff --git a/yamllint/config.py b/yamllint/config.py
index 4fc9ef6..939fe4a 100644
--- a/yamllint/config.py
+++ b/yamllint/config.py
@@ -25,7 +25,7 @@ class YamlLintConfigError(Exception):
     pass
 
 
-class YamlLintConfig(object):
+class YamlLintConfig:
     def __init__(self, content=None, file=None):
         assert (content is None) ^ (file is None)
 
diff --git a/yamllint/parser.py b/yamllint/parser.py
index 086613f..d6b71d9 100644
--- a/yamllint/parser.py
+++ b/yamllint/parser.py
@@ -16,7 +16,7 @@
 import yaml
 
 
-class Line(object):
+class Line:
     def __init__(self, line_no, buffer, start, end):
         self.line_no = line_no
         self.start = start
@@ -28,7 +28,7 @@ class Line(object):
         return self.buffer[self.start:self.end]
 
 
-class Token(object):
+class Token:
     def __init__(self, line_no, curr, prev, next, nextnext):
         self.line_no = line_no
         self.curr = curr
@@ -37,7 +37,7 @@ class Token(object):
         self.nextnext = nextnext
 
 
-class Comment(object):
+class Comment:
     def __init__(self, line_no, column_no, buffer, pointer,
                  token_before=None, token_after=None, comment_before=None):
         self.line_no = line_no
diff --git a/yamllint/rules/indentation.py b/yamllint/rules/indentation.py
index dfee0f2..3853f6f 100644
--- a/yamllint/rules/indentation.py
+++ b/yamllint/rules/indentation.py
@@ -218,7 +218,7 @@ ROOT, B_MAP, F_MAP, B_SEQ, F_SEQ, B_ENT, KEY, VAL = range(8)
 labels = ('ROOT', 'B_MAP', 'F_MAP', 'B_SEQ', 'F_SEQ', 'B_ENT', 'KEY', 'VAL')
 
 
-class Parent(object):
+class Parent:
     def __init__(self, type, indent, line_indent=None):
         self.type = type
         self.indent = indent
diff --git a/yamllint/rules/key_duplicates.py b/yamllint/rules/key_duplicates.py
index 371d2ed..3f93e7d 100644
--- a/yamllint/rules/key_duplicates.py
+++ b/yamllint/rules/key_duplicates.py
@@ -64,7 +64,7 @@ TYPE = 'token'
 MAP, SEQ = range(2)
 
 
-class Parent(object):
+class Parent:
     def __init__(self, type):
         self.type = type
         self.keys = []