Leslie Egerton Blackwell was a Canadian politiican.

He was first elected to the Ontario legislature in the 1943 Ontario election that brought George Drew's Ontario Progressive Conservative Party to power with a minority government Blackwell, representing the Toronto riding of Eglinton was immediately put into cabinet as Attorney-General. During Blackwell's term he oversaw the passing into law of the Ontario Human Rights Code making the province the second jurisdiction in North America to implement such legislation (the first was New York State).

After Drew's departure from provincial politics, Blackwell ran in the 1949 provincial Tory leadership convention placing second to Leslie Frost. He did not join Frost's cabinet and resigned his seat in the legislature the next year.