John Thomas Hackett, QC (June 12, 1884 – September 15, 1956) was a Canadian lawyer and politician.

He was born in Stanstead, Quebec, the son of Michael Felix Hackett and Florence Alberta Knight, and was educated at St. Charles Seminary and the law school at McGill University.

[1] He was also president of the Stanstead County Historical Society and a lieutenant in the militia.

In 1948, while serving as the president of the Canadian Bar Association and MP for Stanstead, Hackett spoke in the House of Commons against a proposal that the position of chief commissioner of the Board of Transport Commissioners be designated as open only to a judge of the Exchequer Court of Canada.

Hackett was concerned that the proposal would blur the lines between the quasi-political and policy role of the Board, compared to the traditional neutrality of judges, and could undermine popular respect for the judiciary as neutral arbiters.