William Wallen may refer to:
William Wallén (born 1991), Swedish ice hockey forward William Wallen Sr. (1790–1873), English architect and surveyor in London William Wallen Jr. (1817–1891), English architect and surveyor in London William Wallen (architect, born 1807) (1807–1888), English architect who practiced in London and Huddersfield, Yorkshire
See also Wallen (disambiguation)