Franco-Ontarians or franco-ontariens are francophone (French-speaking) residents of the Canadian province of Ontario. According to the 2001 Canadian census, there were 548,940 francophones in Ontario, comprising 4.8 per cent of the province's total population. Franco-Ontarians constitute the largest French-speaking community in Canada outside of Quebec.

The Franco-Ontarian population is concentrated primarily in Northeastern Ontario, in the cities of Sudbury, North Bay and Timmins and a number of smaller towns, and in Eastern Ontario, in Ottawa and the rural farming communities to the east. However, there are also smaller pockets of francophone population elsewhere in the province.

The Franco-Ontarian flag consists of two bands of green and white. The left portion has a solid light green background with a white fleur-de-lys in the middle, while the right portion has a solid white background with a stylized green trillium in the middle. The green represents the summer months, while the white represents the winter months. The trillium is the floral symbol of Ontario, while the fleur-de-lys represents the French heritage of the Franco-Ontarian community. The flag was designed in 1975 by a group of university students in Sudbury, and flown for the first time at Laurentian University.

The Ontario government's French Language Services Act of 1986 designates 23 areas of the province where provincial ministries and agencies are required to provide French-language services to the public. The provincial government also operates a French-language public television network, TFO, which serves most communities in the province on cable, but is also available over the air in a number of francophone communities. The Office of Francophone Affairs is the government agency responsible for ensuring that French language services are provided.

The dialect of French spoken in Ontario is similar to but distinct from that which prevails in Québec. Due to the large English majority in the province, many English words are simply used in place of the proper French words when speaking French. One example is "un truck" or "un pickup" to refer to a pickup truck, when the proper French word is "camion".