diff --git a/buildhub/api/views.py b/buildhub/api/views.py
index 9871a5a1..f84a7abf 100644
--- a/buildhub/api/views.py
+++ b/buildhub/api/views.py
@@ -7,6 +7,7 @@
 
 import markus
 from django import http
+from django.conf import settings
 from elasticsearch.exceptions import RequestError
 
 from buildhub.main.models import Build
@@ -25,6 +26,11 @@ def search(request):
     if request.method in ("POST",):
         arguments = json.loads(request.body.decode("utf-8"))
         if arguments:
+            if arguments.get("size") and arguments["size"] > settings.MAX_SEARCH_SIZE:
+                return http.JsonResponse(
+                    {"error": f"Search size too large ({arguments['size']})"},
+                    status=400,
+                )
             try:
                 search.update_from_dict(arguments)
             except ValueError as exception:
diff --git a/buildhub/settings.py b/buildhub/settings.py
index e5723bd7..b9d1c681 100644
--- a/buildhub/settings.py
+++ b/buildhub/settings.py
@@ -181,6 +181,9 @@ def ES_BUILD_INDEX_SETTINGS(self):
     def ES_CONNECTIONS(self):
         return {"default": {"hosts": self.ES_URLS}}
 
+    # To prevent the ES search query from being too big.
+    MAX_SEARCH_SIZE = values.IntegerValue(1000)
+
 
 class OptionalDatabaseURLValue(values.DatabaseURLValue):
     def caster(self, url, **options):
diff --git a/tests/test_api_views.py b/tests/test_api_views.py
index 52eef394..93ceb65c 100644
--- a/tests/test_api_views.py
+++ b/tests/test_api_views.py
@@ -122,6 +122,15 @@ def test_search_empty_filter(valid_build, json_poster, elasticsearch):
     )
 
 
+@pytest.mark.django_db
+def test_search_unbound_size(valid_build, json_poster, elasticsearch, settings):
+    search = {"query": {"match_all": {}}, "size": settings.MAX_SEARCH_SIZE + 1}
+    url = reverse("api:search")
+    response = json_poster(url, search)
+    assert response.status_code == 400
+    assert response.json()["error"] == "Search size too large (1001)"
+
+
 @pytest.mark.django_db
 def test_happy_path_records(valid_build, client, elasticsearch):
     url = reverse("api:records")