diff --git a/elasticsearch-model/lib/elasticsearch/model/multimodel.rb b/elasticsearch-model/lib/elasticsearch/model/multimodel.rb
index 2c2306274..f9ef2eaea 100644
--- a/elasticsearch-model/lib/elasticsearch/model/multimodel.rb
+++ b/elasticsearch-model/lib/elasticsearch/model/multimodel.rb
@@ -85,7 +85,7 @@ def index_name
       # @return [Array] the list of document types used for retrieving documents
       #
       def document_type
-        models.map { |m| m.document_type }
+        models.map { |m| m.document_type }.compact.presence
       end
 
       # Get the client common for all models