Leslie Egerton Blackwell was a Canadian politician, soldier, lawyer, and land developer.

During the 1937 Ontario general election Blackwell was a candidate in Toronto’s Eglinton electoral district where he came in second on election night. He ran again in Eglinton, and was elected to the Legislative Assembly of Ontario in the 1943 election that brought George Drew’s Progressive Conservative Party of Ontario to power with a minority government. Blackwell was immediately put into Drew’s cabinet as Attorney General.

After Drew’s departure from provincial politics, Blackwell was a candidate to replace him in the 1949 Conservative leadership election, placing second to Leslie Frost. He did not join Frost’s cabinet and served his remaining time as a backbencher in the legislature, and did not run in the 1951 election.