Lemuel John Tweedie (November 30, 1849 – July 15, 1917) was a Canadian politician.
His law partner in Chatham, New Brunswick for a time was Richard Bedford Bennett, later Prime Minister of Canada; and for a time Max Aitken was his office boy.
A former supporter of the federal Conservatives, he joined the Liberal Cabinet of New Brunswick Premier Andrew George Blair serving as Surveyor-General and Provincial Secretary in successive Liberal governments. Tweedie became Premier of the province in 1900 and led the party to a large majority government in the 1903 election.
Tweedie's government allowed women to be admitted to the practice of law in 1906 and supported the development of hydroelectric power at Grand Falls. He also created a Workers' Compensation board and successfully lobbied the federal government to increase subsidies to the province including payment for railway expansion. He led the government for seven years before becoming the 12th Lieutenant Governor of New Brunswick, holding that position until 1912.