diff --git a/app/controllers/users_controller.rb b/app/controllers/users_controller.rb
index 646473862..24d2fe99e 100644
--- a/app/controllers/users_controller.rb
+++ b/app/controllers/users_controller.rb
@@ -288,7 +288,7 @@ class UsersController < ApplicationController
   end
 
   def search_users
-    term = (params[:term] || "").strip.downcase
+    term = params[:term].to_s.strip
     topic_id = params[:topic_id]
     topic_id = topic_id.to_i if topic_id
 
diff --git a/app/models/user_search.rb b/app/models/user_search.rb
index 3795bee6c..b8ccb91e2 100644
--- a/app/models/user_search.rb
+++ b/app/models/user_search.rb
@@ -14,7 +14,7 @@ class UserSearch
     end
 
     if term.length > 0
-      sql << "where username_lower like :term_like or
+      sql << "where username ilike :term_like or
               to_tsvector('simple', name) @@
               to_tsquery('simple',
                 regexp_replace(
diff --git a/spec/controllers/users_controller/search_users_spec.rb b/spec/controllers/users_controller/search_users_spec.rb
index 0b23545ba..732c7bba4 100644
--- a/spec/controllers/users_controller/search_users_spec.rb
+++ b/spec/controllers/users_controller/search_users_spec.rb
@@ -59,6 +59,16 @@ describe UsersController, :search_users do
       json = JSON.parse(response.body)
       json["users"].size.should == 3
     end
+
+    it "searches the user's username substring upper case" do
+      xhr :post, :search_users, term: "MR"
+      json = JSON.parse(response.body)
+      json["users"].size.should == 6
+
+      xhr :post, :search_users, term: "MRB"
+      json = JSON.parse(response.body)
+      json["users"].size.should == 3
+    end
   end
 
   context "sort order respects users with posts on the topic" do