S.O. (CAN) - Statutes of Ontario Jurisdiction: Canada Related Citation: R.S.O. Capital S followed by a capital O, with periods, as in S.O. Statutes of Ontario. Annual statutes of the Canadian Province of Ontario. Frequently need citation information? Try our search provider (works in most modern browsers) If you find an error, omission or if have a suggestion for a law report, legal periodical or abbreviation, we'd love to get your input!