diff --git a/app/services/projects/update_service.rb b/app/services/projects/update_service.rb
index 0e489ec5e86..0d1e2e758cd 100644
--- a/app/services/projects/update_service.rb
+++ b/app/services/projects/update_service.rb
@@ -38,7 +38,7 @@ module Projects
     end
 
     def run_auto_devops_pipeline?
-      return false if project.repository.gitlab_ci_yml || !project.auto_devops.previous_changes.include?('enabled')
+      return false if project.repository.gitlab_ci_yml || !project.auto_devops&.previous_changes&.include?('enabled')
 
       project.auto_devops.enabled? || (project.auto_devops.enabled.nil? && Gitlab::CurrentSettings.auto_devops_enabled?)
     end
diff --git a/changelogs/unreleased/46452-nomethoderror-undefined-method-previous_changes-for-nil-nilclass.yml b/changelogs/unreleased/46452-nomethoderror-undefined-method-previous_changes-for-nil-nilclass.yml
new file mode 100644
index 00000000000..89dee65f5a8
--- /dev/null
+++ b/changelogs/unreleased/46452-nomethoderror-undefined-method-previous_changes-for-nil-nilclass.yml
@@ -0,0 +1,5 @@
+---
+title: Check for nil AutoDevOps when saving project CI/CD settings.
+merge_request: 19190
+author:
+type: fixed
diff --git a/spec/services/projects/update_service_spec.rb b/spec/services/projects/update_service_spec.rb
index 3e6073b9861..1f761bcbbad 100644
--- a/spec/services/projects/update_service_spec.rb
+++ b/spec/services/projects/update_service_spec.rb
@@ -275,6 +275,10 @@ describe Projects::UpdateService do
       it { is_expected.to eq(false) }
     end
 
+    context 'when auto devops is nil' do
+      it { is_expected.to eq(false) }
+    end
+
     context 'when auto devops is explicitly enabled' do
       before do
         project.create_auto_devops!(enabled: true)