diff --git a/tenacity/__init__.py b/tenacity/__init__.py
index ebc4b142..c9ea8933 100644
--- a/tenacity/__init__.py
+++ b/tenacity/__init__.py
@@ -22,7 +22,7 @@
 import time
 import typing as t
 import warnings
-from abc import ABCMeta, abstractmethod
+from abc import ABC, abstractmethod
 from concurrent import futures
 from inspect import iscoroutinefunction
 
@@ -225,7 +225,7 @@ def __exit__(
             return None
 
 
-class BaseRetrying(metaclass=ABCMeta):
+class BaseRetrying(ABC):
     def __init__(
         self,
         sleep: t.Callable[[t.Union[int, float]], None] = sleep,
diff --git a/tenacity/retry.py b/tenacity/retry.py
index d62bd663..04db430c 100644
--- a/tenacity/retry.py
+++ b/tenacity/retry.py
@@ -22,7 +22,7 @@
     from tenacity import RetryCallState
 
 
-class retry_base(metaclass=abc.ABCMeta):
+class retry_base(abc.ABC):
     """Abstract base class for retry strategies."""
 
     @abc.abstractmethod
diff --git a/tenacity/stop.py b/tenacity/stop.py
index 24dcd1f4..35072244 100644
--- a/tenacity/stop.py
+++ b/tenacity/stop.py
@@ -22,7 +22,7 @@
     from tenacity import RetryCallState
 
 
-class stop_base(metaclass=abc.ABCMeta):
+class stop_base(abc.ABC):
     """Abstract base class for stop strategies."""
 
     @abc.abstractmethod
diff --git a/tenacity/wait.py b/tenacity/wait.py
index 5ff9b739..2c1f4fb6 100644
--- a/tenacity/wait.py
+++ b/tenacity/wait.py
@@ -24,7 +24,7 @@
     from tenacity import RetryCallState
 
 
-class wait_base(metaclass=abc.ABCMeta):
+class wait_base(abc.ABC):
     """Abstract base class for wait strategies."""
 
     @abc.abstractmethod