diff --git a/rest_framework/authentication.py b/rest_framework/authentication.py
index 382abf158..bb30537f3 100644
--- a/rest_framework/authentication.py
+++ b/rest_framework/authentication.py
@@ -106,7 +106,7 @@ class BasicAuthentication(BaseAuthentication):
         return (user, None)
 
     def authenticate_header(self, request):
-        return 'Basic realm="%s"' % self.www_authenticate_realm
+        return f'Basic realm="{self.www_authenticate_realm}"'
 
 
 class SessionAuthentication(BaseAuthentication):
@@ -145,7 +145,7 @@ class SessionAuthentication(BaseAuthentication):
         reason = check.process_view(request, None, (), {})
         if reason:
             # CSRF failed, bail with explicit error message
-            raise exceptions.PermissionDenied('CSRF Failed: %s' % reason)
+            raise exceptions.PermissionDenied(f'CSRF Failed: {reason}')
 
 
 class TokenAuthentication(BaseAuthentication):
diff --git a/rest_framework/utils/mediatypes.py b/rest_framework/utils/mediatypes.py
index 40bdf2615..b3ea5446b 100644
--- a/rest_framework/utils/mediatypes.py
+++ b/rest_framework/utils/mediatypes.py
@@ -77,7 +77,7 @@ class _MediaType:
         return 3
 
     def __str__(self):
-        ret = "%s/%s" % (self.main_type, self.sub_type)
+        ret = f"{self.main_type}/{self.sub_type}"
         for key, val in self.params.items():
-            ret += "; %s=%s" % (key, val.decode('ascii'))
+            ret += f"; {key}={val.decode('ascii')}"
         return ret
diff --git a/rest_framework/utils/representation.py b/rest_framework/utils/representation.py
index 6f2efee16..19380c4c3 100644
--- a/rest_framework/utils/representation.py
+++ b/rest_framework/utils/representation.py
@@ -19,7 +19,7 @@ def manager_repr(value):
     ]
     for manager_name, manager_instance in names_and_managers:
         if manager_instance == value:
-            return '%s.%s.all()' % (model._meta.object_name, manager_name)
+            return f'{model._meta.object_name}.{manager_name}.all()'
     return repr(value)
 
 
diff --git a/rest_framework/views.py b/rest_framework/views.py
index 5b0622069..0b00d2134 100644
--- a/rest_framework/views.py
+++ b/rest_framework/views.py
@@ -88,7 +88,7 @@ def exception_handler(exc, context):
         if getattr(exc, 'auth_header', None):
             headers['WWW-Authenticate'] = exc.auth_header
         if getattr(exc, 'wait', None):
-            headers['Retry-After'] = '%d' % exc.wait
+            headers['Retry-After'] = f'{exc.wait}'
 
         if isinstance(exc.detail, (list, dict)):
             data = exc.detail
diff --git a/rest_framework/viewsets.py b/rest_framework/viewsets.py
index d69d2157c..1d01a70be 100644
--- a/rest_framework/viewsets.py
+++ b/rest_framework/viewsets.py
@@ -88,17 +88,17 @@ class ViewSetMixin:
         # sanitize keyword arguments
         for key in initkwargs:
             if key in cls.http_method_names:
-                raise TypeError("You tried to pass in the %s method name as a "
-                                "keyword argument to %s(). Don't do that."
-                                % (key, cls.__name__))
+                raise TypeError(f"You tried to pass in the {key} method name as a "
+                                f"keyword argument to {cls.__name__}(). Don't do that."
+                                )
             if not hasattr(cls, key):
                 raise TypeError("%s() received an invalid keyword %r" % (
                     cls.__name__, key))
 
         # name and suffix are mutually exclusive
         if 'name' in initkwargs and 'suffix' in initkwargs:
-            raise TypeError("%s() received both `name` and `suffix`, which are "
-                            "mutually exclusive arguments." % (cls.__name__))
+            raise TypeError(f"{cls.__name__}() received both `name` and `suffix`, which are "
+                            "mutually exclusive arguments.")
 
         def view(request, *args, **kwargs):
             self = cls(**initkwargs)
@@ -158,7 +158,7 @@ class ViewSetMixin:
         """
         Reverse the action for the given `url_name`.
         """
-        url_name = '%s-%s' % (self.basename, url_name)
+        url_name = f'{self.basename}-{url_name}'
         namespace = None
         if self.request and self.request.resolver_match:
             namespace = self.request.resolver_match.namespace
diff --git a/tests/generic_relations/models.py b/tests/generic_relations/models.py
index 20df3e4a2..1e2c0bd23 100644
--- a/tests/generic_relations/models.py
+++ b/tests/generic_relations/models.py
@@ -26,7 +26,7 @@ class Bookmark(models.Model):
     tags = GenericRelation(Tag)
 
     def __str__(self):
-        return 'Bookmark: %s' % self.url
+        return f'Bookmark: {self.url}'
 
 
 class Note(models.Model):
@@ -37,4 +37,4 @@ class Note(models.Model):
     tags = GenericRelation(Tag)
 
     def __str__(self):
-        return 'Note: %s' % self.text
+        return f'Note: {self.text}'
diff --git a/tests/test_fields.py b/tests/test_fields.py
index 7a5304a82..173b1dade 100644
--- a/tests/test_fields.py
+++ b/tests/test_fields.py
@@ -2310,7 +2310,7 @@ class TestSerializerMethodField:
             example_field = serializers.SerializerMethodField()
 
             def get_example_field(self, obj):
-                return 'ran get_example_field(%d)' % obj['example_field']
+                return f'ran get_example_field({obj["example_field"]})'
 
         serializer = ExampleSerializer({'example_field': 123})
         assert serializer.data == {