John Powell (June 19, 1809 – February 24, 1881) was a Canadian politician who served as mayor of Toronto and played an important role in the Upper Canada Rebellion.

When former mayor William Lyon Mackenzie attempted to foment a rebellion against the Compact and Governor Sir Francis Bond Head, Powell became an important member of the forces opposing him.

On the night of December 4, Powell and companion Archibald Macdonald left the central part of town to investigate the reports of rebel activities to the north.

Unbeknownst to them the rebels had captured a local armoury and were based at Montgomery's Tavern, preparing to march south.

His main preoccupation was security, organizing local militias in each ward and expanding the small police force to help suppress future disorder.