The music and arts festival is to run July 3-12.
Clarkson is scheduled to perform at the Pengrowth Saddledome July 9.
Other stars scheduled to perform are Taylor Swift on July 8; Kenny Chesney on July 10 and George Strait on July 11.
This will be the only Canadian summer date for Clarkson, who was the first "American Idol" winner and the first "American Idol" alumnus to score two No. 1 albums, organizers said.
"The Stampede is delighted with the addition of Kelly Clarkson to the entertainment lineup at this year's Greatest Outdoor Show on Earth," Paul Rosenberg, Calgary Stampede vice president of programming, said in a statement. "With her latest album hitting No. 1 in its first week, Clarkson's star continues to rise and she is clearly a performer we look forward to bringing to the Stampede."