diff --git a/datasette/templates/query.html b/datasette/templates/query.html
index 8dd1037f..91bd7a2a 100644
--- a/datasette/templates/query.html
+++ b/datasette/templates/query.html
@@ -37,7 +37,7 @@
 
 {% block description_source_license %}{% include "_description_source_license.html" %}{% endblock %}
 
-<form class="sql core" action="{{ urls.database(database) }}{% if stored_query %}/{{ stored_query }}{% endif %}" method="{% if stored_query_write %}post{% else %}get{% endif %}" data-parameters-url="{{ urls.database(database) }}/-/query/parameters">
+<form class="sql core" action="{% if stored_query %}{{ urls.query(database, stored_query) }}{% else %}{{ urls.database(database) }}/-/query{% endif %}" method="{% if stored_query_write %}post{% else %}get{% endif %}" data-parameters-url="{{ urls.database(database) }}/-/query/parameters">
     <h3>Custom SQL query{% if display_rows %} returning {% if truncated %}more than {% endif %}{{ "{:,}".format(display_rows|length) }} row{% if display_rows|length == 1 %}{% else %}s{% endif %}{% endif %}{% if not query_error %}
         <span class="show-hide-sql">(<a href="{{ show_hide_link }}">{{ show_hide_text }}</a>)</span>
     {% endif %}</h3>
diff --git a/tests/test_query_form_action.py b/tests/test_query_form_action.py
new file mode 100644
index 00000000..8f419d55
--- /dev/null
+++ b/tests/test_query_form_action.py
@@ -0,0 +1,53 @@
+import pytest
+from bs4 import BeautifulSoup as Soup
+
+
+@pytest.mark.asyncio
+async def test_ad_hoc_query_form_targets_query_route(ds_client):
+    response = await ds_client.get("/fixtures/-/query?sql=select+1")
+    assert response.status_code == 200
+
+    form = Soup(response.text, "html.parser").select_one("form.sql.core")
+    assert form is not None
+    assert form["action"] == "/fixtures/-/query"
+
+
+def test_ad_hoc_query_form_action_preserves_base_url(app_client_base_url_prefix):
+    response = app_client_base_url_prefix.get("/prefix/fixtures/-/query?sql=select+1")
+    assert response.status_code == 200
+
+    form = Soup(response.text, "html.parser").select_one("form.sql.core")
+    assert form is not None
+    assert form["action"] == "/prefix/fixtures/-/query"
+
+
+@pytest.mark.asyncio
+async def test_stored_query_form_action_encodes_query_name(ds_client):
+    query_name = "query with spaces"
+    await ds_client.ds.update_query("fixtures", query_name, sql="select 1")
+    query_url = ds_client.ds.urls.query("fixtures", query_name)
+
+    response = await ds_client.get(query_url)
+    assert response.status_code == 200
+
+    form = Soup(response.text, "html.parser").select_one("form.sql.core")
+    assert form is not None
+    assert form["action"] == query_url
+
+
+@pytest.mark.asyncio
+async def test_stored_query_form_action_preserves_base_url(
+    app_client_base_url_prefix,
+):
+    query_name = "query with spaces"
+    await app_client_base_url_prefix.ds.update_query(
+        "fixtures", query_name, sql="select 1"
+    )
+    query_url = app_client_base_url_prefix.ds.urls.query("fixtures", query_name)
+
+    response = app_client_base_url_prefix.get(query_url)
+    assert response.status_code == 200
+
+    form = Soup(response.text, "html.parser").select_one("form.sql.core")
+    assert form is not None
+    assert form["action"] == query_url