diff --git a/AUTHORS b/AUTHORS
index bfba0c0523..909149137d 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -382,6 +382,7 @@ answer newbie questions, and generally made Django that much better:
     Jensen Cochran <jensen.cochran@gmail.com>
     Jeong-Min Lee <falsetru@gmail.com>
     Jérémie Blaser <blaserje@gmail.com>
+    Jeremy Bowman <https://github.com/jmbowman>
     Jeremy Carbaugh <jcarbaugh@gmail.com>
     Jeremy Dunck <jdunck@gmail.com>
     Jeremy Lainé <jeremy.laine@m4x.org>
diff --git a/django/db/backends/base/schema.py b/django/db/backends/base/schema.py
index bd07385672..cf18e7653e 100644
--- a/django/db/backends/base/schema.py
+++ b/django/db/backends/base/schema.py
@@ -14,12 +14,28 @@ from django.utils.encoding import force_bytes
 logger = logging.getLogger('django.db.backends.schema')
 
 
+def _is_relevant_relation(relation, altered_field):
+    """
+    When altering the given field, must constraints on its model from the given
+    relation be temporarily dropped?
+    """
+    field = relation.field
+    if field.many_to_many:
+        # M2M reverse field
+        return False
+    if altered_field.primary_key and field.to_fields == [None]:
+        # Foreign key constraint on the primary key, which is being altered.
+        return True
+    # Is the constraint targeting the field being altered?
+    return altered_field.name in field.to_fields
+
+
 def _related_non_m2m_objects(old_field, new_field):
     # Filter out m2m objects from reverse relations.
     # Return (old_relation, new_relation) tuples.
     return zip(
-        (obj for obj in old_field.model._meta.related_objects if not obj.field.many_to_many),
-        (obj for obj in new_field.model._meta.related_objects if not obj.field.many_to_many)
+        (obj for obj in old_field.model._meta.related_objects if _is_relevant_relation(obj, old_field)),
+        (obj for obj in new_field.model._meta.related_objects if _is_relevant_relation(obj, new_field))
     )
 
 
@@ -731,7 +747,7 @@ class BaseDatabaseSchemaEditor:
         # Rebuild FKs that pointed to us if we previously had to drop them
         if drop_foreign_keys:
             for rel in new_field.model._meta.related_objects:
-                if not rel.many_to_many and rel.field.db_constraint:
+                if _is_relevant_relation(rel, new_field) and rel.field.db_constraint:
                     self.execute(self._create_fk_sql(rel.related_model, rel.field, "_fk"))
         # Does it have check constraints we need to add?
         if old_db_params['check'] != new_db_params['check'] and new_db_params['check']:
diff --git a/docs/releases/1.11.13.txt b/docs/releases/1.11.13.txt
index 8dbd651652..b9fd3329ef 100644
--- a/docs/releases/1.11.13.txt
+++ b/docs/releases/1.11.13.txt
@@ -9,4 +9,6 @@ Django 1.11.13 fixes several bugs in 1.11.12.
 Bugfixes
 ========
 
-* ...
+* Fixed a regression in Django 1.11.8 where altering a field with a unique
+  constraint may drop and rebuild more foreign keys than necessary
+  (:ticket:`29193`).
diff --git a/docs/releases/2.0.5.txt b/docs/releases/2.0.5.txt
index c7a7a84d9e..c88135aeb9 100644
--- a/docs/releases/2.0.5.txt
+++ b/docs/releases/2.0.5.txt
@@ -11,3 +11,7 @@ Bugfixes
 
 * Corrected the import paths that ``inspectdb`` generates for
   ``django.contrib.postgres`` fields (:ticket:`29307`).
+
+* Fixed a regression in Django 1.11.8 where altering a field with a unique
+  constraint may drop and rebuild more foreign keys than necessary
+  (:ticket:`29193`).
diff --git a/tests/schema/tests.py b/tests/schema/tests.py
index 12c33a8433..b535a834f9 100644
--- a/tests/schema/tests.py
+++ b/tests/schema/tests.py
@@ -1545,6 +1545,40 @@ class SchemaTests(TransactionTestCase):
             TagUniqueRename.objects.create(title="bar", slug2="foo")
         Tag.objects.all().delete()
 
+    @isolate_apps('schema')
+    @unittest.skipIf(connection.vendor == 'sqlite', 'SQLite naively remakes the table on field alteration.')
+    @skipUnlessDBFeature('supports_foreign_keys')
+    def test_unique_no_unnecessary_fk_drops(self):
+        """
+        If AlterField isn't selective about dropping foreign key constraints
+        when modifying a field with a unique constraint, the AlterField
+        incorrectly drops and recreates the Book.author foreign key even though
+        it doesn't restrict the field being changed (#29193).
+        """
+        class Author(Model):
+            name = CharField(max_length=254, unique=True)
+
+            class Meta:
+                app_label = 'schema'
+
+        class Book(Model):
+            author = ForeignKey(Author, CASCADE)
+
+            class Meta:
+                app_label = 'schema'
+
+        with connection.schema_editor() as editor:
+            editor.create_model(Author)
+            editor.create_model(Book)
+        new_field = CharField(max_length=255, unique=True)
+        new_field.model = Author
+        new_field.set_attributes_from_name('name')
+        with patch_logger('django.db.backends.schema', 'debug') as logger_calls:
+            with connection.schema_editor() as editor:
+                editor.alter_field(Author, Author._meta.get_field('name'), new_field)
+            # One SQL statement is executed to alter the field.
+            self.assertEqual(len(logger_calls), 1)
+
     @isolate_apps('schema')
     @unittest.skipIf(connection.vendor == 'sqlite', 'SQLite remakes the table on field alteration.')
     def test_unique_and_reverse_m2m(self):