The deal adds two years to Kubiak's original contract, the Texans said on their website (www.houstontexans.com).
Kubiak has a 31-33 record in four seasons with the Texans. He led Houston to a 9-7 record in 2009, the eight-year-old franchise's first winning season.
"I think Gary has done a very good job," owner Bob McNair told a news conference. "We've still got a long, long way to go," Kubiak said. "But I think we've got the right group of guys to do it."
Houston finished second in the AFC South and won its final four games.
(Reporting by Gene Cherry in Salvo, North Carolina. Editing by Alison Wildey)