diff --git a/changelogs/fragments/31735-fix-hostnames-lookup-order.yaml b/changelogs/fragments/31735-fix-hostnames-lookup-order.yaml
new file mode 100644
index 00000000000..fe90db33b68
--- /dev/null
+++ b/changelogs/fragments/31735-fix-hostnames-lookup-order.yaml
@@ -0,0 +1,2 @@
+bugfixes:
+  - inventory_hostnames lookup - use the same order for the returned hosts as the inventory manager
diff --git a/lib/ansible/inventory/manager.py b/lib/ansible/inventory/manager.py
index 10785aa7938..cc43e4e4682 100644
--- a/lib/ansible/inventory/manager.py
+++ b/lib/ansible/inventory/manager.py
@@ -36,6 +36,7 @@ from ansible.module_utils.six import string_types
 from ansible.module_utils._text import to_bytes, to_text
 from ansible.parsing.utils.addresses import parse_address
 from ansible.plugins.loader import inventory_loader
+from ansible.utils.helpers import deduplicate_list
 from ansible.utils.path import unfrackpath
 from ansible.utils.display import Display
 
@@ -369,8 +370,7 @@ class InventoryManager(object):
                     # exclude hosts mentioned in any restriction (ex: failed hosts)
                     hosts = [h for h in hosts if h.name in self._restriction]
 
-                seen = set()
-                self._hosts_patterns_cache[pattern_hash] = [x for x in hosts if x not in seen and not seen.add(x)]
+                self._hosts_patterns_cache[pattern_hash] = deduplicate_list(hosts)
 
             # sort hosts list if needed (should only happen when called from strategy)
             if order in ['sorted', 'reverse_sorted']:
diff --git a/lib/ansible/plugins/lookup/inventory_hostnames.py b/lib/ansible/plugins/lookup/inventory_hostnames.py
index f04cd8ff326..001abdbab39 100644
--- a/lib/ansible/plugins/lookup/inventory_hostnames.py
+++ b/lib/ansible/plugins/lookup/inventory_hostnames.py
@@ -36,6 +36,7 @@ RETURN = """
 
 from ansible.inventory.manager import split_host_pattern, order_patterns
 from ansible.plugins.lookup import LookupBase
+from ansible.utils.helpers import deduplicate_list
 
 
 class LookupModule(LookupBase):
@@ -70,4 +71,4 @@ class LookupModule(LookupBase):
                     host_list.extend(that)
 
         # return unique list
-        return list(set(host_list))
+        return deduplicate_list(host_list)
diff --git a/lib/ansible/utils/helpers.py b/lib/ansible/utils/helpers.py
index 900e0d1ac3a..658ad99c968 100644
--- a/lib/ansible/utils/helpers.py
+++ b/lib/ansible/utils/helpers.py
@@ -41,3 +41,11 @@ def object_to_dict(obj, exclude=None):
     if exclude is None or not isinstance(exclude, list):
         exclude = []
     return dict((key, getattr(obj, key)) for key in dir(obj) if not (key.startswith('_') or key in exclude))
+
+
+def deduplicate_list(original_list):
+    """
+    Creates a deduplicated list with the order in which each item is first found.
+    """
+    seen = set()
+    return [x for x in original_list if x not in seen and not seen.add(x)]
diff --git a/test/integration/targets/lookup_inventory_hostnames/aliases b/test/integration/targets/lookup_inventory_hostnames/aliases
new file mode 100644
index 00000000000..765b70da796
--- /dev/null
+++ b/test/integration/targets/lookup_inventory_hostnames/aliases
@@ -0,0 +1 @@
+shippable/posix/group2
diff --git a/test/integration/targets/lookup_inventory_hostnames/inventory b/test/integration/targets/lookup_inventory_hostnames/inventory
new file mode 100644
index 00000000000..1b968af2991
--- /dev/null
+++ b/test/integration/targets/lookup_inventory_hostnames/inventory
@@ -0,0 +1,6 @@
+[group01]
+test01
+test05
+test03
+test02
+test04
diff --git a/test/integration/targets/lookup_inventory_hostnames/main.yml b/test/integration/targets/lookup_inventory_hostnames/main.yml
new file mode 100644
index 00000000000..afc09ea86e3
--- /dev/null
+++ b/test/integration/targets/lookup_inventory_hostnames/main.yml
@@ -0,0 +1,13 @@
+---
+- hosts: localhost
+  gather_facts: no
+  tasks:
+  - set_fact:
+      hosts_a: "{{ lookup('inventory_hostnames', 'group01', wantlist=true) }}"
+
+  - set_fact:
+      hosts_b: "{{ groups['group01'] }}"
+
+  - assert:
+      that:
+        - hosts_a == hosts_b
diff --git a/test/integration/targets/lookup_inventory_hostnames/runme.sh b/test/integration/targets/lookup_inventory_hostnames/runme.sh
new file mode 100755
index 00000000000..8f4b7231915
--- /dev/null
+++ b/test/integration/targets/lookup_inventory_hostnames/runme.sh
@@ -0,0 +1,5 @@
+#!/usr/bin/env bash
+
+set -eux
+
+ansible-playbook main.yml -i inventory -e "$@"