There are many affiliated groups that are important to Rangi Ruru and with which the school works closely.

These include the

• Parent Community
• Parent Teachers Association (PTA)
• Board of Governors (comprised of representatives and nominees of school staff, parents, Old Girls, the Presbyterian Church and PTA)
• Rangi Trust - a group which oversees school investments on behalf of the Board of Governors
• Rangi Ruru Old Girls' Association (RROGA) - an active group of former students
• Friends of Rangi Ruru - a social group of people who have an interest in Rangi Ruru