William Henderson (February 26, 1837 – September 24, 1931) was a Scottish-born architect who mainly worked in Canada.

In 1861 he moved back to Scotland, where he married his first wife, Mary Jane Smith.

In 1872 he moved back to Ottawa as an overseer for the Federal department of public works in Canada.

This position meant he was responsible as site supervisor for all federal buildings being built in the province.

A biographer described Henderson as " highly respected and admired, and his record in public life, as well as his efforts in behalf of all movements tending towards the moral uplift of the community, places him in the foremost rank of Victoria's estimable citizens.