diff --git a/datasette/app.py b/datasette/app.py
index afe20258ca..eb5bd54101 100644
--- a/datasette/app.py
+++ b/datasette/app.py
@@ -3,7 +3,7 @@
 from sanic.exceptions import NotFound
 from sanic.views import HTTPMethodView
 from sanic.request import RequestParameters
-from jinja2 import Environment, FileSystemLoader
+from jinja2 import Environment, FileSystemLoader, ChoiceLoader, PrefixLoader
 import re
 import sqlite3
 from pathlib import Path
@@ -43,15 +43,13 @@
 
 
 class RenderMixin(HTTPMethodView):
-    def render(self, template, **context):
+    def render(self, templates, **context):
         return response.html(
-            self.jinja_env.get_template(template).render(**context)
+            self.jinja_env.select_template(templates).render(**context)
         )
 
 
 class BaseView(RenderMixin):
-    template = None
-
     def __init__(self, datasette):
         self.ds = datasette
         self.files = datasette.files
@@ -166,6 +164,9 @@ def sql_operation_in_thread():
             self.executor, sql_operation_in_thread
         )
 
+    def get_templates(self, database, table=None):
+        assert NotImplemented
+
     async def get(self, request, db_name, **kwargs):
         name, hash, should_redirect = self.resolve_db_name(db_name, **kwargs)
         if should_redirect:
@@ -179,8 +180,8 @@ async def view_get(self, request, name, hash, **kwargs):
             as_json = False
         extra_template_data = {}
         start = time.time()
-        template = self.template
         status_code = 200
+        templates = []
         try:
             response_or_template_contexts = await self.data(
                 request, name, hash, **kwargs
@@ -188,7 +189,7 @@ async def view_get(self, request, name, hash, **kwargs):
             if isinstance(response_or_template_contexts, response.HTTPResponse):
                 return response_or_template_contexts
             else:
-                data, extra_template_data = response_or_template_contexts
+                data, extra_template_data, templates = response_or_template_contexts
         except (sqlite3.OperationalError, InvalidSql) as e:
             data = {
                 'ok': False,
@@ -196,8 +197,8 @@ async def view_get(self, request, name, hash, **kwargs):
                 'database': name,
                 'database_hash': hash,
             }
-            template = 'error.html'
             status_code = 400
+            templates = ['error.html']
         end = time.time()
         data['query_ms'] = (end - start) * 1000
         for key in ('source', 'source_url', 'license', 'license_url'):
@@ -246,7 +247,7 @@ async def view_get(self, request, name, hash, **kwargs):
                 }
             }
             r = self.render(
-                template,
+                templates,
                 **context,
             )
             r.status = status_code
@@ -300,7 +301,7 @@ async def get(self, request, as_json):
             )
         else:
             return self.render(
-                'index.html',
+                ['index.html'],
                 databases=databases,
                 metadata=self.ds.metadata,
                 datasette_version=__version__,
@@ -314,7 +315,6 @@ async def favicon(request):
 
 
 class DatabaseView(BaseView):
-    template = 'database.html'
     re_named_parameter = re.compile(':([a-zA-Z0-9_]+)')
 
     async def data(self, request, name, hash):
@@ -331,7 +331,7 @@ async def data(self, request, name, hash):
         }, {
             'database_hash': hash,
             'show_hidden': request.args.get('_show_hidden'),
-        }
+        }, ('database-{}.html'.format(to_css_class(name)), 'database.html')
 
     async def custom_sql(self, request, name, hash):
         params = request.raw_args
@@ -370,7 +370,7 @@ async def custom_sql(self, request, name, hash):
             'database_hash': hash,
             'custom_sql': True,
             'named_parameter_values': named_parameter_values,
-        }
+        }, ('database-{}.html'.format(to_css_class(name)), 'database.html')
 
 
 class DatabaseDownload(BaseView):
@@ -464,8 +464,6 @@ async def make_display_rows(self, database, database_hash, table, rows, display_
 
 
 class TableView(RowTableShared):
-    template = 'table.html'
-
     async def data(self, request, name, hash, table):
         table = urllib.parse.unquote_plus(table)
         pks = await self.pks_for_table(name, table)
@@ -681,12 +679,13 @@ async def extra_template():
             },
             'next': next_value and str(next_value) or None,
             'next_url': next_url,
-        }, extra_template
+        }, extra_template, (
+            'table-{}-{}.html'.format(to_css_class(name), to_css_class(table)),
+            'table.html'
+        )
 
 
 class RowView(RowTableShared):
-    template = 'row.html'
-
     async def data(self, request, name, hash, table, pk_path):
         table = urllib.parse.unquote_plus(table)
         pk_values = compound_pks_from_path(pk_path)
@@ -733,7 +732,10 @@ async def template_data():
         if 'foreign_key_tables' in (request.raw_args.get('_extras') or '').split(','):
             data['foreign_key_tables'] = await self.foreign_key_tables(name, table, pk_values)
 
-        return data, template_data
+        return data, template_data, (
+            'row-{}-{}.html'.format(to_css_class(name), to_css_class(table)),
+            'row.html'
+        )
 
     async def foreign_key_tables(self, name, table, pk_values):
         if len(pk_values) != 1:
@@ -893,12 +895,19 @@ def inspect(self):
 
     def app(self):
         app = Sanic(__name__)
-        template_paths = []
+        default_templates = str(app_root / 'datasette' / 'templates')
         if self.template_dir:
-            template_paths.append(self.template_dir)
-        template_paths.append(str(app_root / 'datasette' / 'templates'))
+            template_loader = ChoiceLoader([
+                FileSystemLoader([self.template_dir, default_templates]),
+                # Support {% extends "default:table.html" %}:
+                PrefixLoader({
+                    'default': FileSystemLoader(default_templates),
+                }, delimiter=':')
+            ])
+        else:
+            template_loader = FileSystemLoader(default_templates)
         self.jinja_env = Environment(
-            loader=FileSystemLoader(template_paths),
+            loader=template_loader,
             autoescape=True,
         )
         self.jinja_env.filters['escape_css_string'] = escape_css_string