Alexandre Keil (1830–1897) was a Portuguese naval officer who briefly served as the chief of the Portuguese Navy during the reign of King Carlos I of Portugal. He rose through the ranks of the fleet and was eventually appointed navy commander in 1894, but the King was soon disatisfied with what he viewed as Keil's failures in regards to colonial conflicts in Africa. Keil was sacked and forced to go into retirement barely a year after his appointment, and died a broken man in 1897.