William Buell (October 5, 1751 – August 8, 1832) was an American-born jurist, miller and political figure in Upper Canada.
He was born in Hebron, Connecticut in 1751, to Timothy Buell and Mercy Peters. His father attempted to remain neutral during the American Revolution and was persecuted as a result. His son chose to side with the British and moved to Montreal at the beginning of the war. He served as assistant Quartermaster in General John Burgoyne's army. After the surrender at Saratoga, he joined the King's Rangers of Robert Rogers as an ensign and eventually rose to rank of Lieutenant.
In 1784, he settled in Elizabethtown Township then part of western Quebec near what was to become Brockville. He set up a mill in the area. In 1788, he was appointed justice of the peace in the Lunenburg District and in the Midland District in 1796. In 1800, he was elected to the 3rd Parliament of Upper Canada for Leeds. He opened the first school in Brockville in his own home and donated land for the courthouse and several churches. He helped his son, William Jr., buy the Brockville Recorder; his son also represented Leeds in the Legislative Assembly.