Tagg, Matt, Josh, Ben and Craig Romney are scheduled to sit down with O'Brien on Conan on Wednesday, June 20.
This will mark the late-night chat show debut of the five brothers, as well as their first joint interview of the campaign.
Conan airs weeknights at 11pm ET on TBS.
Mitt is currently running for the US presidency against Barack Obama.
The pair recently appeared in the opening video sketch at the 2012 CMT Awards.
Watch the sketch featuring Barack Obama and Mitt Romney below: