diff --git a/capistrano-sidekiq.gemspec b/capistrano-sidekiq.gemspec
index a655f18..28ee34e 100644
--- a/capistrano-sidekiq.gemspec
+++ b/capistrano-sidekiq.gemspec
@@ -18,5 +18,5 @@ Gem::Specification.new do |spec|
   spec.require_paths = ['lib']
 
   spec.add_dependency 'capistrano', '>= 3.9.0'
-  spec.add_dependency 'sidekiq', '>= 3.4'
+  spec.add_dependency 'sidekiq', '>= 3.4', '< 6'
 end