The movie's world premiere is scheduled for March 11 at the 2012 SXSW Film Festival.
Red Flag, which will handle theatrical distribution, is a fledgling independent film distribution company founded by Paul Federbush and Laura Kim and New York-based producer Ron Stein.
Fox Searchlight will handle ancillary markets.
"The Do-Deca-Pentathlon" is about two grown brothers who revive their childhood sporting competition during a weekend family reunion, to decide, once and for all, which of the two is the champion. But the competition annoys the rest of the family, so the brothers hide their efforts to complete the competition.
Steve Zissis, Mark Kelly and Jennifer Lafleur star.
The Duplass Bros. wrote and directed the comedy, which Stephanie Langhoff produced.
Jay and Mark Duplass wrote and directed "Jeff Who Lives at Home," starring Jason Segel, Ed Helms and Susan Sarandon, the 2010 Sundance hit "Cyrus," the 2008 "Baghead" and the 2005 "The Puffy Chair."