diff --git a/lib/searchkick.rb b/lib/searchkick.rb
index 77da93f..a82c995 100644
--- a/lib/searchkick.rb
+++ b/lib/searchkick.rb
@@ -128,11 +128,6 @@ module Searchkick
       end
     end
 
-    # TODO raise ArgumentError in next major version
-    unless klass || options[:models]
-      Searchkick.warn("missing keyword: :models")
-    end
-
     options = options.merge(block: block) if block
     query = Searchkick::Query.new(klass, term, **options)
     if options[:execute] == false
diff --git a/lib/searchkick/results.rb b/lib/searchkick/results.rb
index a1bf847..6c0b2d4 100644
--- a/lib/searchkick/results.rb
+++ b/lib/searchkick/results.rb
@@ -231,7 +231,7 @@ module Searchkick
                 index_alias = index.split("_")[0..-2].join("_")
                 Array((options[:index_mapping] || {})[index_alias])
               end
-            raise Searchkick::Error, "Unknown model for index: #{index}" unless models.any?
+            raise Searchkick::Error, "Unknown model for index: #{index}. Pass the `models` option to the search method." unless models.any?
             index_models[index] = models
           end
 
diff --git a/test/multi_indices_test.rb b/test/multi_indices_test.rb
index ade0c13..cf1d7de 100644
--- a/test/multi_indices_test.rb
+++ b/test/multi_indices_test.rb
@@ -44,13 +44,15 @@ class MultiIndicesTest < Minitest::Test
   def test_no_models_or_index_name
     store_names ["Product A"]
 
-    # TODO raise ArgumentError in next major version
-    assert_output(nil, /missing keyword: :models/) do
-      error = assert_raises(Searchkick::Error) do
-        Searchkick.search("product").results
-      end
-      assert_includes error.message, "Unknown model"
+    error = assert_raises(Searchkick::Error) do
+      Searchkick.search("product").results
     end
+    assert_includes error.message, "Unknown model"
+  end
+
+  def test_no_models_or_index_name_load_false
+    store_names ["Product A"]
+    Searchkick.search("product", load: false).results
   end
 
   private
--
libgit2 0.21.0