History

Municipal associations in Ontario have a long history consisting of numerous amalgamations and mergers of separate organizations. The first meeting of an enduring municipal association was held in Hamilton on September 6, 1899. The name "Ontario Municipal Association" was chosen, and it was agreed that there would be annual meetings, or "oftener if need be, upon the call of the executive committee", so that both appointed and elected representatives of municipalities could discuss common concerns. A constitution for the organization was drawn up, officers elected and the mandate decided ‑ to establish regular meetings between the association and the government to speak to, and to influence legislation.

The Association of Municipalities of Ontario was created through the merger and reconstitution of the Ontario Municipal Association and the Ontario Association of Mayors and Reeves on June 22, 1972. Further organizational change continued to be discussed in the late 1970s when exploratory meetings were held between AMO and two other major municipal organizations which also existed at that time: The Rural Ontario Municipal Association and The Association of Counties and Regions. Discussions were also held with affiliated associations: The Organization of Small Urban Municipalities (OSUM), The Association of District Municipalities, The Federation of Northern Ontario Municipalities (FONOM), and The Northwestern Ontario Municipal Association (NOMA).

In February 1980, an Association Review Committee was struck and presented its report in June 1980. A new association of municipal representatives was proposed, consisting of five sections, "restructured to ensure accurate representation of the positions of the different types of municipalities in the province". The newly constituted Association of Municipalities of Ontario came into being on January 1, 1982.  In May of 1990 AMO became formally incorporated without share capital. AMO's constitution was re‑formulated into governing By‑law No.1. The By‑law has been amended a number of times to implement significant changes to the Association.