In 1972, The Ontario Association of Children's Mental Health Centres (OACMHC) was established by its member centres. Through the Association, children's mental health centres began sharing information and advocating for policies, programs, and funds to improve the state of children's mental health throughout the province.

The Ontario Association of Children's Mental Health Centres (OACMHC) changed its name to Children's Mental Health Ontario (CMHO) in 1999. This new name signifies a broader, more child-focused emphasis, and reflects a recognition that children's mental health centres are one part of comprehensive system of health and social services. In other words, we are part of a larger children's mental health system, and we must all work together.