diff --git a/lib/logstash/pluginmanager/command.rb b/lib/logstash/pluginmanager/command.rb
index 2a2c7508c87..692a126ab4b 100644
--- a/lib/logstash/pluginmanager/command.rb
+++ b/lib/logstash/pluginmanager/command.rb
@@ -32,6 +32,7 @@ def remove_unused_locally_installed_gems!
   end
 
   def relative_path(path)
-    Pathname.new(path).relative_path_from(Pathname.new(LogStash::Environment::LOGSTASH_HOME)).to_s
+    require "pathname"
+    ::Pathname.new(path).relative_path_from(::Pathname.new(LogStash::Environment::LOGSTASH_HOME)).to_s
   end
 end