Simpson was named a West Division all-star for the third time in 2013 after recording 56 tackles, six sacks, one interception, two forced fumbles, one fumble recovery and six pass knockdowns.
The 29-year-old Alabama product was the West Division finalist for the CFL's most outstanding defensive player award in 2010.
"Juwan has been a valuable and consistent performer in the middle of our defence for a number of years and I'm pleased that he has chosen to remain with the Stampeders," Stampeders head coach and general manager John Hufnagel said in a statement. "I'm fully expecting him to maintain his high level of play for us going forward."
In six seasons with Calgary, Simpson has 294 tackles, 41 special-teams tackles, 18 sacks, two interceptions, eight fumble recoveries and eight forced fumbles.
"I joined the Stampeders back in 2008 and I'm very glad to be staying," Simpson said in a release. "It's very rare to spend your entire career with one team and I feel fortunate that I have the opportunity to do that. Coach Huff is one of the best coaches I've ever played for, the Stampeders are a top organization and Calgary is a second home for me. I'm looking forward to bigger and better things."