Sion Longley Wenban was an American landscape painter and etcher.

He spent his childhood in Cleveland. He first studied at the New York Art Academy, then briefly entered the Munich Academy in 1878, here pupil of Gabriel von Hackl, then further trained with Frank Duveneck in Polling. He was acquainted with and supported by Frank Currier (1843-1909).

Wenban was a founding member and board member of the "Munich Association for Original Etching" in 1891.