The former X-Factor semi-finalists are the first act to headline the event, and will perform on Glasgow Green on Saturday 22nd August.
The band have previously performed at other Prides, and will this year be again providing live entertainment at a number of Pride events across Britain including Leeds.
Union J are likely to prove popular with many Pride attendees and their headlining of the Glasgow event underlines just how much Pride Glasgow has grown in the last few years.
Jaymi Hensley, one of the original members of Union J, is openly gay and hopes to marry his partner of six years, Olly Marmon, later this year.
Glasgow Pride 2015 will, for the first time, take place over a full weekend. Tickets are available now, with Weekend Early Bird tickets costing £10 with day tickets priced at £8.
More information can be found on Pride Glasgow’s website.