Riot Games

Video game maker of the popular League of Legends franchise boasts that 73% of its population are millennials. The company, which was featured in Fortune’s 2015 Best Companies to Work For, “is known for its team-played online game, League of Legends; employees say the company culture is no less team-centered. Staffers are so united they collectively call themselves Rioters, and 95 percent say the company has a family or team feel,” according to Great Place to Work. Read the Great Place to Work review.