diff --git a/kafka/consumer/subscription_state.py b/kafka/consumer/subscription_state.py
index 2540303f2..2a7810569 100644
--- a/kafka/consumer/subscription_state.py
+++ b/kafka/consumer/subscription_state.py
@@ -497,7 +497,7 @@ def is_fetchable(self):
         return not self.paused and self.has_valid_position
 
 
-class ConsumerRebalanceListener(object, metaclass=abc.ABCMeta):
+class ConsumerRebalanceListener(metaclass=abc.ABCMeta):
     """
     A callback interface that the user can implement to trigger custom actions
     when the set of partitions assigned to the consumer changes.
diff --git a/kafka/coordinator/assignors/abstract.py b/kafka/coordinator/assignors/abstract.py
index a9ae5bbdf..10115190f 100644
--- a/kafka/coordinator/assignors/abstract.py
+++ b/kafka/coordinator/assignors/abstract.py
@@ -5,7 +5,7 @@
 )
 
 
-class AbstractPartitionAssignor:
+class AbstractPartitionAssignor(metaclass=abc.ABCMeta):
     """
     Abstract assignor implementation which does some common grunt work (in particular collecting
     partition counts which are always needed in assignors).
diff --git a/kafka/coordinator/base.py b/kafka/coordinator/base.py
index 717ca5f29..f7ea75fa0 100644
--- a/kafka/coordinator/base.py
+++ b/kafka/coordinator/base.py
@@ -57,7 +57,7 @@ class UnjoinedGroupException(Errors.KafkaError):
     retriable = True
 
 
-class BaseCoordinator:
+class BaseCoordinator(metaclass=abc.ABCMeta):
     """
     BaseCoordinator implements group management for a single group member
     by interacting with a designated Kafka broker (the coordinator). Group
diff --git a/kafka/metrics/measurable.py b/kafka/metrics/measurable.py
index fd5be1205..1abd222c3 100644
--- a/kafka/metrics/measurable.py
+++ b/kafka/metrics/measurable.py
@@ -1,7 +1,7 @@
 import abc
 
 
-class AbstractMeasurable:
+class AbstractMeasurable(metaclass=abc.ABCMeta):
     """A measurable quantity that can be registered as a metric"""
     @abc.abstractmethod
     def measure(self, config, now):