Yoo Seung-jun
- Birthday: 1992-05-01
- Place of birth: South Korea
- Also know as: 유승준
He is a MR.MR. former member with stage name Joon. He joined the group as a sixth member in November 2013 and left in February 2014 due to controversy spread by his old friend. He has a YouTube channel with his friend Zeze.
