diff --git a/greenhouse_io.gemspec b/greenhouse_io.gemspec
index 8980dca..c096961 100644
--- a/greenhouse_io.gemspec
+++ b/greenhouse_io.gemspec
@@ -21,7 +21,7 @@ Gem::Specification.new do |spec|
   spec.add_dependency('httmultiparty', '~> 0.3.16')
   spec.required_ruby_version = '>= 1.9.3'
 
-  spec.add_development_dependency "bundler", "~> 1.3"
+  spec.add_development_dependency "bundler", "~> 2.1"
   spec.add_development_dependency "rake"
   spec.add_development_dependency "rspec", "~> 3.4.0"
   spec.add_development_dependency "webmock", "~> 1.22.6"