diff --git a/django/contrib/contenttypes/generic.py b/django/contrib/contenttypes/generic.py
index 389692d..c6d9f30 100644
--- a/django/contrib/contenttypes/generic.py
+++ b/django/contrib/contenttypes/generic.py
@@ -406,6 +406,10 @@ class GenericInlineModelAdmin(InlineModelAdmin):
         else:
             exclude = list(self.exclude)
         exclude.extend(self.get_readonly_fields(request, obj))
+        if self.exclude is None and hasattr(self.form, '_meta') and self.form._meta.exclude:
+            # Take the custom ModelForm's Meta.exclude into account only if the
+            # GenericInlineModelAdmin doesn't define its own.
+            exclude.extend(self.form.Meta.exclude)
         exclude = exclude or None
         defaults = {
             "ct_field": self.ct_field,
diff --git a/tests/regressiontests/generic_inline_admin/models.py b/tests/regressiontests/generic_inline_admin/models.py
index fb6363e..32ecd3b 100644
--- a/tests/regressiontests/generic_inline_admin/models.py
+++ b/tests/regressiontests/generic_inline_admin/models.py
@@ -5,6 +5,8 @@ from django.contrib.contenttypes.models import ContentType
 
 class Episode(models.Model):
     name = models.CharField(max_length=100)
+    length = models.CharField(max_length=100, blank=True)
+    author = models.CharField(max_length=100, blank=True)
 
 class Media(models.Model):
     """
@@ -14,6 +16,8 @@ class Media(models.Model):
     object_id = models.PositiveIntegerField()
     content_object = generic.GenericForeignKey()
     url = models.URLField(verify_exists=False)
+    description = models.CharField(max_length=100, blank=True)
+    keywords = models.CharField(max_length=100, blank=True)
 
     def __unicode__(self):
         return self.url
@@ -59,18 +63,6 @@ class MediaMaxNumInline(generic.GenericTabularInline):
 
 admin.site.register(EpisodeMaxNum, inlines=[MediaMaxNumInline])
 
-#
-# Generic inline with exclude
-#
-
-class EpisodeExclude(Episode):
-    pass
-
-class MediaExcludeInline(generic.GenericTabularInline):
-    model = Media
-    exclude = ['url']
-
-admin.site.register(EpisodeExclude, inlines=[MediaExcludeInline])
 
 #
 # Generic inline with unique_together
diff --git a/tests/regressiontests/generic_inline_admin/tests.py b/tests/regressiontests/generic_inline_admin/tests.py
index 00badc9..da59922 100644
--- a/tests/regressiontests/generic_inline_admin/tests.py
+++ b/tests/regressiontests/generic_inline_admin/tests.py
@@ -1,13 +1,16 @@
 # coding: utf-8
 
 from django.conf import settings
+from django.contrib import admin
 from django.contrib.admin.sites import AdminSite
-from django.contrib.contenttypes.generic import generic_inlineformset_factory
+from django.contrib.contenttypes.generic import (
+    generic_inlineformset_factory, GenericTabularInline)
+from django.forms.models import ModelForm
 from django.test import TestCase
 
 # local test models
-from models import (Episode, EpisodeExtra, EpisodeMaxNum, EpisodeExclude,
-    Media, MediaInline, EpisodePermanent, MediaPermanentInline, Category)
+from models import (Episode, EpisodeExtra, EpisodeMaxNum, Media,
+    MediaInline, EpisodePermanent, MediaPermanentInline, Category)
 
 
 class GenericAdminViewTest(TestCase):
@@ -88,7 +91,7 @@ class GenericAdminViewTest(TestCase):
         self.assertEqual(response.status_code, 302) # redirect somewhere
 
     def testGenericInlineFormset(self):
-        EpisodeMediaFormSet = generic_inlineformset_factory(Media, can_delete=False, extra=3)
+        EpisodeMediaFormSet = generic_inlineformset_factory(Media, can_delete=False, exclude=['description', 'keywords'], extra=3)
         e = Episode.objects.get(name='This Week in Django')
 
         # Works with no queryset
@@ -105,7 +108,6 @@ class GenericAdminViewTest(TestCase):
         self.assertEqual(formset.forms[1].as_p(), '<p><label for="id_generic_inline_admin-media-content_type-object_id-1-url">Url:</label> <input id="id_generic_inline_admin-media-content_type-object_id-1-url" type="text" name="generic_inline_admin-media-content_type-object_id-1-url" value="http://example.com/podcast.mp3" maxlength="200" /><input type="hidden" name="generic_inline_admin-media-content_type-object_id-1-id" value="%s" id="id_generic_inline_admin-media-content_type-object_id-1-id" /></p>' % self.mp3_media_pk)
         self.assertEqual(formset.forms[2].as_p(), '<p><label for="id_generic_inline_admin-media-content_type-object_id-2-url">Url:</label> <input id="id_generic_inline_admin-media-content_type-object_id-2-url" type="text" name="generic_inline_admin-media-content_type-object_id-2-url" maxlength="200" /><input type="hidden" name="generic_inline_admin-media-content_type-object_id-2-id" id="id_generic_inline_admin-media-content_type-object_id-2-id" /></p>')
 
-
         # Works with a queryset that omits items
         formset = EpisodeMediaFormSet(instance=e, queryset=Media.objects.filter(url__endswith=".png"))
         self.assertEqual(len(formset.forms), 4)
@@ -173,14 +175,6 @@ class GenericInlineAdminParametersTest(TestCase):
         self.assertEqual(formset.total_form_count(), 2)
         self.assertEqual(formset.initial_form_count(), 1)
 
-    def testExcludeParam(self):
-        """
-        Generic inline formsets should respect include.
-        """
-        e = self._create_object(EpisodeExclude)
-        response = self.client.get('/generic_inline_admin/admin/generic_inline_admin/episodeexclude/%s/' % e.pk)
-        formset = response.context['inline_admin_formsets'][0].formset
-        self.assertFalse('url' in formset.forms[0], 'The formset has excluded "url" field.')
 
 class GenericInlineAdminWithUniqueTogetherTest(TestCase):
     fixtures = ['users.xml']
@@ -218,6 +212,9 @@ class NoInlineDeletionTest(TestCase):
 
 class GenericInlineModelAdminTest(TestCase):
 
+    def setUp(self):
+        self.site = AdminSite()
+
     def test_get_formset_kwargs(self):
         media_inline = MediaInline(Media, AdminSite())
 
@@ -230,3 +227,82 @@ class GenericInlineModelAdminTest(TestCase):
         formset = media_inline.get_formset(None, max_num=100, can_order=True)
         self.assertEqual(formset.max_num, 100)
         self.assertEqual(formset.can_order, True)
+
+    def test_custom_form_meta_exclude_with_readonly(self):
+        """
+        Ensure that the custom ModelForm's `Meta.exclude` is respected when
+        used in conjunction with `GenericInlineModelAdmin.readonly_fields`
+        and when no `ModelAdmin.exclude` is defined.
+        """
+
+        request = None
+
+        class MediaForm(ModelForm):
+
+            class Meta:
+                model = Media
+                exclude = ['url']
+
+        class MediaInline(GenericTabularInline):
+            readonly_fields = ['description']
+            form = MediaForm
+            model = Media
+
+        class EpisodeAdmin(admin.ModelAdmin):
+            inlines = [
+                MediaInline
+            ]
+
+        ma = EpisodeAdmin(Episode, self.site)
+        self.assertEqual(
+            list(ma.get_formsets(request))[0]().forms[0].fields.keys(),
+            ['keywords', 'id', 'DELETE'])
+
+    def test_custom_form_meta_exclude(self):
+        """
+        Ensure that the custom ModelForm's `Meta.exclude` is respected by
+        `GenericInlineModelAdmin.get_formset`, and overridden if
+        `ModelAdmin.exclude` or `GenericInlineModelAdmin.exclude` are defined.
+        Refs #15907.
+        """
+
+        request = None
+
+        # First with `GenericInlineModelAdmin`  -----------------
+
+        class MediaForm(ModelForm):
+
+            class Meta:
+                model = Media
+                exclude = ['url']
+
+        class MediaInline(GenericTabularInline):
+            exclude = ['description']
+            form = MediaForm
+            model = Media
+
+        class EpisodeAdmin(admin.ModelAdmin):
+            inlines = [
+                MediaInline
+            ]
+
+        ma = EpisodeAdmin(Episode, self.site)
+        self.assertEqual(
+            list(ma.get_formsets(request))[0]().forms[0].fields.keys(),
+            ['url', 'keywords', 'id', 'DELETE'])
+
+        # Then, only with `ModelForm`  -----------------
+
+        class MediaInline(GenericTabularInline):
+            form = MediaForm
+            model = Media
+
+        class EpisodeAdmin(admin.ModelAdmin):
+            inlines = [
+                MediaInline
+            ]
+
+        ma = EpisodeAdmin(Episode, self.site)
+        self.assertEqual(
+            list(ma.get_formsets(request))[0]().forms[0].fields.keys(),
+            ['description', 'keywords', 'id', 'DELETE'])
