Alexander Slidell Mackenzie (April 6, 1803 - September 13, 1848), born Alexander Slidell, was a United States Navy officer, famous for his 1842 decision to execute three suspected mutineers aboard a ship under his command in the Somers Mutiny. Mackenzie was also an accomplished man of letters, producing several volumes of travel writing and biographies of early important US naval figures, some of whom he knew personally.

Mackenzie was the