diff --git a/datasette/templates/base.html b/datasette/templates/base.html
index afb8dcd3da..51f602b66e 100644
--- a/datasette/templates/base.html
+++ b/datasette/templates/base.html
@@ -1,5 +1,5 @@
 {% import "_crumbs.html" as crumbs with context %}<!DOCTYPE html>
-<html>
+<html lang="en">
 <head>
     <title>{% block title %}{% endblock %}</title>
     <link rel="stylesheet" href="{{ urls.static('app.css') }}?{{ app_css_hash }}">
diff --git a/datasette/templates/patterns.html b/datasette/templates/patterns.html
index cb0daf9a8e..24fe55314e 100644
--- a/datasette/templates/patterns.html
+++ b/datasette/templates/patterns.html
@@ -1,5 +1,5 @@
 <!DOCTYPE html>
-<html>
+<html lang="en">
 <head>
     <title>Datasette: Pattern Portfolio</title>
     <link rel="stylesheet" href="{{ base_url }}-/static/app.css?{{ app_css_hash }}">
diff --git a/tests/test_html.py b/tests/test_html.py
index de732d2c47..a83f0e47db 100644
--- a/tests/test_html.py
+++ b/tests/test_html.py
@@ -21,6 +21,8 @@ def test_homepage(app_client_two_attached_databases):
     response = app_client_two_attached_databases.get("/")
     assert response.status_code == 200
     assert "text/html; charset=utf-8" == response.headers["content-type"]
+    # Should have a html lang="en" attribute
+    assert '<html lang="en">' in response.text
     soup = Soup(response.content, "html.parser")
     assert "Datasette Fixtures" == soup.find("h1").text
     assert (
