The Association of Municipalities of Ontario (AMO) is a non-profit organization representing almost all of Ontario’s 445 municipal governments and provides a variety of services and products to members and non-members.

The mandate of the organization is to support and enhance strong and effective municipal government in Ontario. It promotes the value of the municipal level of government as a vital and essential component of Ontario and Canada's political system. The Mandate is delivered in a variety of ways. Of particular importance is the Memorandum of Understanding (MOU) between AMO and the Province. The MOU provides the opportunity for municipal input and reaction to provincial policy ideas (pre-consultation) so that they are fully informed as part of any provincial policy making process. The MOU also includes a Protocol that obligates the Province to consult with AMO and municipalities on matters that are of a federal-provincial nature that could affect municipal services and finances. The Protocol also sets out the Province’s commitment to pursue a federal-provincial-municipal framework where municipalities have a ‘seat at the federal-provincial table’.

The activities of AMO support both its mandate and vision statement. AMO develops policy positions and reports on issues of general interest to municipal governments; conducts ongoing liaison with provincial government elected and non-elected representatives; informs and educates governments, the media and the public on municipal issues; markets innovative and beneficial services to the municipal sector; and maintains a resource centre on issues of municipal interest. The Association's Annual Meeting is held in August and is combined with a comprehensive conference program.