Police say the teen was approached by two men while waiting at a bus stop at Taradale Drive and Tara Cove Road N.E. around 11:30 p.m. MT on Friday night.
The girl was dragged into an alley and sexually assaulted, police say.
Later the culprits forcibly walked the teen to a neighbouring community. She was held overnight in a home and repeatedly sexually assaulted, police say.
The girl, who may have suffered a concussion, managed to escape the house around 8 a.m. on Saturday while the culprits were distracted.
The girl fled to her family, who brought her to police. On Sunday morning, three men — two brothers and their father — were taken into custody.
Corey George Manyshots, 25, and Cody George Manyshots, 21, are both charged with kidnapping, uttering threats, sex assault causing body harm and assault causing bodily harm.
They're set for a first court appearance in Calgary on Monday.