The International Order of the Rainbow for Girls is an organization for girls between the ages of 11 and 20. At the age of 20, or upon marriage, which ever occurs first, girls who are members in good standing are eligible for Majority Membership. To join, girl must be sponsored by two other girls who are either active members in good standing or a majority member, and at least one adult whom must be a member in good standing of either the Masonic Lodge, Order of the Eastern Star, Order of the Amaranth or the White Shrine. Members of the Order of the Rainbow for Girls participate in many charitable and civic service projects with in their city and state.

The International Order of the Rainbow for Girls was established in McAlester, Oklahoma in 1922. The very inception and writing of the first Ritual, and the laws governing the Order, was the work of W. Mark Sexson, a 33rd Degree Mason and pastor of the First Christian Church in McAlester, Oklahoma.

Lorraine Assembly # 6 International Order of the Rainbow for Girls is sponsored by Suburban Lodge # 740 Free and Accepted Masons and Southern Star Chapter # 154 Order of the Eastern Star. Members from both organizations serve on the Adult Advisory Board of Lorraine Assembly, these advisors oversee the activities and chaperone all functions and trips.

The members of Lorraine Assembly # 6 are involved in many activities throughout the year, such as preparing fruit baskets for lodge widows, care packages for the Veterans Hospital and Kosair Hospital, and charities such as The Special Olympics and the American Diabetes Foundation. They also have a number of social events, like dances, picnics, and trips to the Kosair Shrine Circus, Kings Island and Kentucky Kingdom.