William Colquhoun (December 23, 1814 – September 2, 1898) was an Ontario businessman and political figure.

He settled at Dickinson's Landing where he was postmaster from 1841 to 1863 and operated a general store.

He was re-elected in Stormont in 1871, but his election was overturned on appeal and he lost (but was victorious) the subsequent by-election in 1872.

He moved to Cornwall, Ontario in 1876, where he was mayor from 1881 to 1883 and also served as justice of the peace.

This article about an Ontario Progressive Conservative Party MPP is a stub.