diff --git docs/api/schemas/latest/patchwork.yaml docs/api/schemas/latest/patchwork.yaml
index 46969000a65b..6c7564baf81b 100644
--- docs/api/schemas/latest/patchwork.yaml
+++ docs/api/schemas/latest/patchwork.yaml
@@ -463,6 +463,13 @@ paths:
             enum:
               - 'true'
               - 'false'
+        - in: query
+          name: hash
+          description: >
+            The patch hash as a case-insensitive hexadecimal string, to filter by.
+          schema:
+            title: ''
+            type: string
       responses:
         '200':
           description: ''
diff --git docs/api/schemas/patchwork.j2 docs/api/schemas/patchwork.j2
index 4fc100eb4a92..12a6f67de32b 100644
--- docs/api/schemas/patchwork.j2
+++ docs/api/schemas/patchwork.j2
@@ -468,6 +468,15 @@ paths:
             enum:
               - 'true'
               - 'false'
+{% if version >= (1, 2) %}
+        - in: query
+          name: hash
+          description: >
+            The patch hash as a case-insensitive hexadecimal string, to filter by.
+          schema:
+            title: ''
+            type: string
+{% endif %}
       responses:
         '200':
           description: ''
diff --git docs/api/schemas/v1.2/patchwork.yaml docs/api/schemas/v1.2/patchwork.yaml
index 2ced470b7dc0..7dc95793faa3 100644
--- docs/api/schemas/v1.2/patchwork.yaml
+++ docs/api/schemas/v1.2/patchwork.yaml
@@ -463,6 +463,13 @@ paths:
             enum:
               - 'true'
               - 'false'
+        - in: query
+          name: hash
+          description: >
+            The patch hash as a case-insensitive hexadecimal string, to filter by.
+          schema:
+            title: ''
+            type: string
       responses:
         '200':
           description: ''
diff --git patchwork/api/filters.py patchwork/api/filters.py
index 37aca82d9ab2..4184ee8253f0 100644
--- patchwork/api/filters.py
+++ patchwork/api/filters.py
@@ -7,6 +7,7 @@ from django.contrib.auth.models import User
 from django.core.exceptions import ValidationError
 from django.db.models import Q
 from django_filters.rest_framework import FilterSet
+from django_filters import CharFilter
 from django_filters import IsoDateTimeFilter
 from django_filters import ModelMultipleChoiceFilter
 from django.forms import ModelMultipleChoiceField as BaseMultipleChoiceField
@@ -176,11 +177,16 @@ class PatchFilterSet(TimestampMixin, FilterSet):
     submitter = PersonFilter(queryset=Person.objects.all())
     delegate = UserFilter(queryset=User.objects.all())
     state = StateFilter(queryset=State.objects.all())
+    hash = CharFilter(lookup_expr='iexact')
 
     class Meta:
         model = Patch
+        # NOTE(dja): ideally we want to version the hash field, but I cannot
+        # find a way to do that which is reliable and not extremely ugly.
+        # The best I can come up with is manually working with request.GET
+        # which seems to rather defeat the point of using django-filters.
         fields = ('project', 'series', 'submitter', 'delegate',
-                  'state', 'archived')
+                  'state', 'archived', 'hash')
 
 
 class CheckFilterSet(TimestampMixin, FilterSet):
diff --git patchwork/tests/api/test_patch.py patchwork/tests/api/test_patch.py
index edae9851c422..4afc15a9ba1c 100644
--- patchwork/tests/api/test_patch.py
+++ patchwork/tests/api/test_patch.py
@@ -22,6 +22,13 @@ from patchwork.tests.utils import create_user
 if settings.ENABLE_REST_API:
     from rest_framework import status
 
+# a diff different from the default, required to test hash filtering
+SAMPLE_DIFF = """--- /dev/null\t2019-01-01 00:00:00.000000000 +0800
++++ a\t2019-01-01 00:00:00.000000000 +0800
+@@ -0,0 +1 @@
++b
+"""
+
 
 @unittest.skipUnless(settings.ENABLE_REST_API, 'requires ENABLE_REST_API')
 class TestPatchAPI(utils.APITestCase):
@@ -152,6 +159,35 @@ class TestPatchAPI(utils.APITestCase):
             'submitter': 'test@example.org'})
         self.assertEqual(0, len(resp.data))
 
+    def test_list_filter_hash(self):
+        """Filter patches by hash."""
+        patch = self._create_patch()
+        patch_new_diff = create_patch(state=patch.state, project=patch.project,
+                                      submitter=patch.submitter,
+                                      diff=SAMPLE_DIFF)
+
+        # check regular filtering
+        resp = self.client.get(self.api_url(), {'hash': patch.hash})
+        self.assertEqual([patch.id], [x['id'] for x in resp.data])
+
+        # 2 patches with identical diffs
+        patch_same_diff = create_patch(state=patch.state,
+                                       project=patch.project,
+                                       submitter=patch.submitter)
+        resp = self.client.get(self.api_url(), {'hash': patch.hash})
+        self.assertEqual([patch.id, patch_same_diff.id],
+                         [x['id'] for x in resp.data])
+
+        # case insensitive matching
+        resp = self.client.get(self.api_url(),
+                               {'hash': patch_new_diff.hash.upper()})
+        self.assertEqual([patch_new_diff.id], [x['id'] for x in resp.data])
+
+        # empty response if nothing matches
+        resp = self.client.get(self.api_url(), {
+            'hash': 'da638d0746a115000bf890fada1f02679aa282e8'})
+        self.assertEqual(0, len(resp.data))
+
     @utils.store_samples('patch-list-1-0')
     def test_list_version_1_0(self):
         """List patches using API v1.0."""
diff --git releasenotes/notes/rest-filter-hash-e031bd3db42eb540.yaml releasenotes/notes/rest-filter-hash-e031bd3db42eb540.yaml
new file mode 100644
index 000000000000..b805931d4d80
--- /dev/null
+++ releasenotes/notes/rest-filter-hash-e031bd3db42eb540.yaml
@@ -0,0 +1,5 @@
+---
+api:
+  - |
+    The REST API now supports filtering patches by their hashes, using the
+    ``hash`` query parameter.
