Big Brothers Big Sisters of Colorado has supported high-quality mentoring relationships between children and adult volunteers for over 91 years. The organization was established as Big Brothers of Denver in 1918 to provide guidance to boys who were increasingly engaging in lawless behavior during World War I. In 1969, Big Sisters of Colorado was formed to address the growing needs for girls in the late sixties. The two organizations merged in 1996 and became Big Brothers Big Sisters of Colorado. In 2001, the organization joined with Big Brothers Big Sisters-Pikes Peak and now operates two offices, one in Denver and one in Colorado Springs.