diff --git a/app/models/namespaces/preloaders/namespace_root_ancestor_preloader.rb b/app/models/namespaces/preloaders/namespace_root_ancestor_preloader.rb
index 467413e0c9ae50e91e35f33b034a69681a84640e..76f297e61cf41854c84f911e0a0e9a0e5f17da36 100644
--- a/app/models/namespaces/preloaders/namespace_root_ancestor_preloader.rb
+++ b/app/models/namespaces/preloaders/namespace_root_ancestor_preloader.rb
@@ -3,6 +3,8 @@
 module Namespaces
   module Preloaders
     class NamespaceRootAncestorPreloader
+      include Gitlab::Loggable
+
       def initialize(namespaces, root_ancestor_preloads = [])
         @namespaces = namespaces
         @root_ancestor_preloads = root_ancestor_preloads
@@ -17,12 +19,30 @@ def execute
         root_ancestors_by_id = root_query.group_by(&:source_id)
 
         @namespaces.each do |namespace|
-          namespace.root_ancestor = root_ancestors_by_id[namespace.id].first
+          root_ancestor = root_ancestors_by_id[namespace.id]&.first
+
+          if root_ancestor
+            namespace.root_ancestor = root_ancestor
+          else
+            log_orphaned_namespace(namespace)
+          end
         end
       end
 
       private
 
+      def log_orphaned_namespace(namespace)
+        Gitlab::AppLogger.warn(
+          build_structured_payload(
+            message: 'Orphaned namespace detected. Unable to find root ancestor',
+            namespace_id: namespace.id,
+            namespace_type: namespace.type,
+            namespace_path: namespace.path,
+            traversal_ids: namespace.traversal_ids
+          )
+        )
+      end
+
       def join_sql
         Namespace.select('id, traversal_ids[1] as root_id').where(id: @namespaces.map(&:id)).to_sql
       end
diff --git a/spec/models/namespaces/preloaders/namespace_root_ancestor_preloader_spec.rb b/spec/models/namespaces/preloaders/namespace_root_ancestor_preloader_spec.rb
index be6254009f9eddad39d6e723c8f2de6f48d8df91..301a927156531a599640d5b2bd65c24e9113089b 100644
--- a/spec/models/namespaces/preloaders/namespace_root_ancestor_preloader_spec.rb
+++ b/spec/models/namespaces/preloaders/namespace_root_ancestor_preloader_spec.rb
@@ -55,6 +55,102 @@
     it_behaves_like 'executes N matching DB queries', 2
   end
 
+  context 'when namespaces have no root ancestor in query results' do
+    it 'safely handles namespaces without root ancestors' do
+      # Create a preloader with an empty namespaces array to simulate
+      # the scenario where the root query returns no matching records
+      expect { described_class.new([], additional_preloads).execute }.not_to raise_error
+    end
+
+    it 'handles case where root_ancestors_by_id lookup returns nil' do
+      namespace = build(:namespace, id: non_existing_record_id)
+      allow(namespace).to receive(:id).and_return(non_existing_record_id)
+
+      preloader = described_class.new([namespace], additional_preloads)
+
+      # Mock the Namespace query to return empty results, simulating the
+      # scenario where no root ancestor is found for the namespace
+      empty_relation = Namespace.none
+      allow(Namespace).to receive(:joins).and_return(empty_relation)
+      allow(empty_relation).to receive_messages(
+        select: empty_relation,
+        preload: empty_relation,
+        group_by: {}
+      )
+
+      expect { preloader.execute }.not_to raise_error
+
+      # Verify that the namespace's root_ancestor instance variable was not set
+      expect(namespace.instance_variable_get(:@root_ancestor)).to be_nil
+    end
+
+    it 'logs orphaned namespace with structured payload when root ancestor is not found' do
+      orphaned_namespace = build(:namespace,
+        id: non_existing_record_id,
+        path: 'orphaned-namespace',
+        type: 'Group',
+        traversal_ids: [123, 456]
+      )
+
+      preloader = described_class.new([orphaned_namespace], additional_preloads)
+
+      # Mock the Namespace query to return empty results
+      empty_relation = Namespace.none
+      allow(Namespace).to receive(:joins).and_return(empty_relation)
+      allow(empty_relation).to receive_messages(
+        select: empty_relation,
+        preload: empty_relation,
+        group_by: {}
+      )
+
+      expected_payload = {
+        'class' => 'Namespaces::Preloaders::NamespaceRootAncestorPreloader',
+        'message' => 'Orphaned namespace detected. Unable to find root ancestor',
+        'namespace_id' => non_existing_record_id,
+        'namespace_type' => 'Group',
+        'namespace_path' => 'orphaned-namespace',
+        'traversal_ids' => [123, 456]
+      }
+
+      expect(Gitlab::AppLogger).to receive(:warn).with(expected_payload)
+
+      preloader.execute
+    end
+
+    context 'when multiple orphaned namespaces exist' do
+      it 'logs each orphaned namespace separately' do
+        orphaned_namespace1 = build(:namespace,
+          id: 9999,
+          path: 'orphaned-1',
+          type: 'Group',
+          traversal_ids: [111]
+        )
+
+        orphaned_namespace2 = build(:namespace,
+          id: 8888,
+          path: 'orphaned-2',
+          type: 'Project',
+          traversal_ids: [222]
+        )
+
+        preloader = described_class.new([orphaned_namespace1, orphaned_namespace2], additional_preloads)
+
+        # Mock the Namespace query to return empty results
+        empty_relation = Namespace.none
+        allow(Namespace).to receive(:joins).and_return(empty_relation)
+        allow(empty_relation).to receive_messages(
+          select: empty_relation,
+          preload: empty_relation,
+          group_by: {}
+        )
+
+        expect(Gitlab::AppLogger).to receive(:warn).twice
+
+        preloader.execute
+      end
+    end
+  end
+
   def preload_ancestors
     described_class.new(pristine_namespaces, additional_preloads).execute
   end