The Assembly of Catholic Bishops of Ontario (ACBO) (Assemblée des évêques catholiques de l'Ontario in French) is the association of Catholic bishops in the Province of Ontario.

It is involved in providing information about the moral positions of the Catholic Church in all aspects of public life.

It works alongside the Canadian Conference of Catholic Bishops on a regional level, while other bishops' assemblies do similar work in other parts of Canada.

[1] In 2021 its president is Ronald Peter Fabbro, bishop of London.

[1] The ACBO includes the bishops of the following Catholic jurisdictions:[1] This article about a Roman Catholic diocese in Canada is a stub.