diff --git a/rest_framework/filters.py b/rest_framework/filters.py
index e68726499..418993405 100644
--- a/rest_framework/filters.py
+++ b/rest_framework/filters.py
@@ -297,7 +297,7 @@ class OrderingFilter(BaseFilterBackend):
             ascending_translation = _("ascending")
             descending_translation = _("descending")
             options.append((key, f'{label} - {ascending_translation}'))
-            options.append(('-' + key, f'{label} - {descending_translation}'))
+            options.append((f'-{key}', f'{label} - {descending_translation}'))
         context['options'] = options
         return context
 
diff --git a/rest_framework/pagination.py b/rest_framework/pagination.py
index e815d8d5c..13a91d753 100644
--- a/rest_framework/pagination.py
+++ b/rest_framework/pagination.py
@@ -118,7 +118,7 @@ def _reverse_ordering(ordering_tuple):
     ordering and return a new tuple, eg. `('created', '-uuid')`.
     """
     def invert(x):
-        return x[1:] if x.startswith('-') else '-' + x
+        return x[1:] if x.startswith('-') else f'-{x}'
 
     return tuple([invert(item) for item in ordering_tuple])
 
diff --git a/rest_framework/renderers.py b/rest_framework/renderers.py
index e8740d57b..068d109c4 100644
--- a/rest_framework/renderers.py
+++ b/rest_framework/renderers.py
@@ -344,7 +344,7 @@ class HTMLFormRenderer(BaseRenderer):
         if 'template' in style:
             template_name = style['template']
         else:
-            template_name = style['template_pack'].strip('/') + '/' + style['base_template']
+            template_name = style['template_pack'].strip('/') + f"/{style['base_template']}"
 
         template = loader.get_template(template_name)
         context = {'field': field, 'style': style}
diff --git a/rest_framework/routers.py b/rest_framework/routers.py
index e0ae24b95..2ee4b457f 100644
--- a/rest_framework/routers.py
+++ b/rest_framework/routers.py
@@ -254,7 +254,7 @@ class SimpleRouter(BaseRouter):
                 #   so a slash in the beginning will (A) cause Django to give
                 #   warnings and (B) generate URLS that will require using '//'.
                 if not prefix and regex[:2] == '^/':
-                    regex = '^' + regex[2:]
+                    regex = f'^{regex[2:]}'
 
                 initkwargs = route.initkwargs.copy()
                 initkwargs.update({
@@ -283,7 +283,7 @@ class APIRootView(views.APIView):
         namespace = request.resolver_match.namespace
         for key, url_name in self.api_root_dict.items():
             if namespace:
-                url_name = namespace + ':' + url_name
+                url_name = f"{namespace}:{url_name}"
             try:
                 ret[key] = reverse(
                     url_name,
diff --git a/rest_framework/schemas/coreapi.py b/rest_framework/schemas/coreapi.py
index 179f0fa3c..c892caae2 100644
--- a/rest_framework/schemas/coreapi.py
+++ b/rest_framework/schemas/coreapi.py
@@ -240,7 +240,7 @@ class SchemaGenerator(BaseSchemaGenerator):
                 # We can just break early in the case that there's at least
                 # one URL that doesn't have a path prefix.
                 return '/'
-            prefixes.append('/' + prefix + '/')
+            prefixes.append(f'/{prefix}/')
         return common_path(prefixes)
 
 # View Inspectors #
diff --git a/rest_framework/schemas/inspectors.py b/rest_framework/schemas/inspectors.py
index 027472db1..94f34637d 100644
--- a/rest_framework/schemas/inspectors.py
+++ b/rest_framework/schemas/inspectors.py
@@ -97,7 +97,7 @@ class ViewInspector:
                 current_section, separator, lead = line.partition(':')
                 sections[current_section] = lead.strip()
             else:
-                sections[current_section] += '\n' + line
+                sections[current_section] += f'\n{line}'
 
         # TODO: SCHEMA_COERCE_METHOD_NAMES appears here and in `SchemaGenerator.get_keys`
         coerce_method_names = api_settings.SCHEMA_COERCE_METHOD_NAMES
diff --git a/rest_framework/serializers.py b/rest_framework/serializers.py
index ac4b92ca8..9d02151fe 100644
--- a/rest_framework/serializers.py
+++ b/rest_framework/serializers.py
@@ -477,7 +477,7 @@ class Serializer(BaseSerializer, metaclass=SerializerMetaclass):
         fields = self._writable_fields
 
         for field in fields:
-            validate_method = getattr(self, 'validate_' + field.field_name, None)
+            validate_method = getattr(self, f'validate_{field.field_name}', None)
             primitive_value = field.get_value(data)
             try:
                 validated_value = field.run_validation(primitive_value)
diff --git a/rest_framework/templatetags/rest_framework.py b/rest_framework/templatetags/rest_framework.py
index 8e35fec6e..c692eca65 100644
--- a/rest_framework/templatetags/rest_framework.py
+++ b/rest_framework/templatetags/rest_framework.py
@@ -187,12 +187,9 @@ def add_class(value, css_class):
     html = str(value)
     match = class_re.search(html)
     if match:
-        m = re.search(r'^%s$|^%s\s|\s%s\s|\s%s$' % (css_class, css_class,
-                                                    css_class, css_class),
-                      match.group(1))
+        m = re.search(fr'[^|\s]{css_class}[$|\s]', match.group(1))
         if not m:
-            return mark_safe(class_re.sub(match.group(1) + " " + css_class,
-                                          html))
+            return mark_safe(class_re.sub(f"{match.group(1)} {css_class}", html))
     else:
         return mark_safe(html.replace('>', f' class="{css_class}">', 1))
     return value
@@ -318,5 +315,5 @@ def break_long_headers(header):
     when possible (are comma separated)
     """
     if len(header) > 160 and ',' in header:
-        header = mark_safe('<br> ' + ', <br>'.join(header.split(',')))
+        header = mark_safe(f"<br> {header.replace(',', ', <br>')}")
     return header
diff --git a/rest_framework/test.py b/rest_framework/test.py
index 0212348ee..d9f93b4c7 100644
--- a/rest_framework/test.py
+++ b/rest_framework/test.py
@@ -171,7 +171,7 @@ class APIRequestFactory(DjangoRequestFactory):
                 "Set TEST_REQUEST_RENDERER_CLASSES to enable "
                 "extra request formats.".format(
                     format,
-                    ', '.join(["'" + fmt + "'" for fmt in self.renderer_classes])
+                    ', '.join([f"'{fmt}'" for fmt in self.renderer_classes])
                 )
             )
 
diff --git a/rest_framework/urlpatterns.py b/rest_framework/urlpatterns.py
index df2afbe51..e4b4aedcb 100644
--- a/rest_framework/urlpatterns.py
+++ b/rest_framework/urlpatterns.py
@@ -11,7 +11,7 @@ def _get_format_path_converter(suffix_kwarg, allowed):
         else:
             allowed_cases = "|".join(allowed)
             allowed_pattern = f'(?:{allowed_cases})'
-        suffix_pattern = r"\.%s/?" % allowed_pattern
+        suffix_pattern = fr"\.{allowed_pattern}/?"
     else:
         suffix_pattern = r"\.[a-z0-9]+/?"
 
@@ -22,7 +22,7 @@ def _get_format_path_converter(suffix_kwarg, allowed):
             return value.strip('./')
 
         def to_url(self, value):
-            return '.' + value + '/'
+            return f'.{value}/'
 
     converter_name = 'drf_format_suffix'
     if allowed:
@@ -102,9 +102,9 @@ def format_suffix_patterns(urlpatterns, suffix_required=False, allowed=None):
         else:
             allowed_cases = "|".join(allowed)
             allowed_pattern = f'({allowed_cases})'
-        suffix_pattern = r'\.(?P<%s>%s)/?$' % (suffix_kwarg, allowed_pattern)
+        suffix_pattern = fr'\.(?P<{suffix_kwarg}>{allowed_pattern})/?$'
     else:
-        suffix_pattern = r'\.(?P<%s>[a-z0-9]+)/?$' % suffix_kwarg
+        suffix_pattern = fr'\.(?P<{suffix_kwarg}>[a-z0-9]+)/?$'
 
     converter_name, suffix_converter = _get_format_path_converter(suffix_kwarg, allowed)
     register_converter(suffix_converter, converter_name)
diff --git a/rest_framework/utils/formatting.py b/rest_framework/utils/formatting.py
index c5917fd41..5d6604721 100644
--- a/rest_framework/utils/formatting.py
+++ b/rest_framework/utils/formatting.py
@@ -63,7 +63,7 @@ def markup_description(description):
         description = apply_markdown(description)
     else:
         description = escape(description).replace('\n', '<br />')
-        description = '<p>' + description + '</p>'
+        description = f'<p>{description}</p>'
     return mark_safe(description)
 
 
diff --git a/rest_framework/utils/html.py b/rest_framework/utils/html.py
index c7ede7803..d10dbcf8e 100644
--- a/rest_framework/utils/html.py
+++ b/rest_framework/utils/html.py
@@ -83,7 +83,7 @@ def parse_html_dict(dictionary, prefix=''):
     }
     """
     ret = MultiValueDict()
-    regex = re.compile(r'^%s\.(.+)$' % re.escape(prefix))
+    regex = re.compile(fr'^{re.escape(prefix)}\.(.+)$')
     for field in dictionary:
         match = regex.match(field)
         if not match:
diff --git a/rest_framework/utils/representation.py b/rest_framework/utils/representation.py
index f50b601f3..4ba6ae83c 100644
--- a/rest_framework/utils/representation.py
+++ b/rest_framework/utils/representation.py
@@ -77,7 +77,7 @@ def serializer_repr(serializer, indent, force_many=None):
         fields = serializer.fields
 
     for field_name, field in fields.items():
-        ret += '\n' + indent_str + field_name + ' = '
+        ret += f'\n{indent_str}{field_name} = '
         if hasattr(field, 'fields'):
             ret += serializer_repr(field, indent + 1)
         elif hasattr(field, 'child'):
diff --git a/rest_framework/versioning.py b/rest_framework/versioning.py
index 78cfc9dc8..72c34f624 100644
--- a/rest_framework/versioning.py
+++ b/rest_framework/versioning.py
@@ -135,7 +135,7 @@ class NamespaceVersioning(BaseVersioning):
         )
 
     def get_versioned_viewname(self, viewname, request):
-        return request.version + ':' + viewname
+        return f"{request.version}:{viewname}"
 
 
 class HostNameVersioning(BaseVersioning):
diff --git a/rest_framework/views.py b/rest_framework/views.py
index 0b00d2134..c76e4f20d 100644
--- a/rest_framework/views.py
+++ b/rest_framework/views.py
@@ -39,7 +39,7 @@ def get_view_name(view):
     # Suffix may be set by some Views, such as a ViewSet.
     suffix = getattr(view, 'suffix', None)
     if suffix:
-        name += ' ' + suffix
+        name += f' {suffix}'
 
     return name
 
diff --git a/rest_framework/viewsets.py b/rest_framework/viewsets.py
index d3988cbcc..926577f41 100644
--- a/rest_framework/viewsets.py
+++ b/rest_framework/viewsets.py
@@ -162,7 +162,7 @@ class ViewSetMixin:
         if self.request and self.request.resolver_match:
             namespace = self.request.resolver_match.namespace
         if namespace:
-            url_name = namespace + ':' + url_name
+            url_name = f"{namespace}:{url_name}"
         kwargs.setdefault('request', self.request)
 
         return reverse(url_name, *args, **kwargs)