Joseph-Octave Arsenault (August 5, 1828 – December 14, 1897) was a Canadian politician who was the first Acadian from Prince Edward Island to be named to the Senate of Canada.

Born in Cascumpec, Prince Edward Island, the son of Mélème Arsenault and Bibienne Poirier, he was a teacher, and later the owner of several businesses, including two general stores and a fish company.

In 1895, he was appointed to the Senate representing the senatorial division of Prince Edward Island.

His son Aubin-Edmond Arsenault was Premier of Prince Edward Island and his son Joseph-Félix Arsenault served in the provincial assembly.

Arsenault played an important role in organizing the first two Acadian national conventions which were held in Memramcook, New Brunswick in 1881 and Miscouche, Prince Edward Island in 1884.