Dennis previous played with the Stamps in 2015 and 2016, starting 23 games and winning the CFL's Most Outstanding Offensive Lineman award in 2016.
The 29-year-old Temple alum spent the 2017 season with the Saskatchewan Roughriders, starting a total of 17 regular-season and playoff games including six at left tackle and 11 at left guard.
"We're obviously very familiar with Derek and I'm pleased that he has agreed to come back to Calgary," said Stampeders president and general manager John Hufnagel. "Derek established himself as one of the top tackles in the CFL during his first stint with the Stamps and I'm looking forward to seeing him play at that high level for us again in 2018."
Prior to first joining the Stamps in 2015, Dennis spent time with a number of NFL teams including Miami, New England, Chicago and Carolina. He played 52 games and made 32 starts over five seasons at Temple.
"I'm excited to be back with the Stamps," said Dennis. "It's a great feeling knowing that I had a chance to return to Calgary and I'm looking forward to picking up where I left off in 2016."