Alexander Montgomery Carlisle (8 July 1854 – 6 March 1926) brother-in-law to Viscount Pirrie, was one of the men involved with designing the Olympic class ocean liners. His main role of responsibility was the ships safety systems such as the watertight compartments, lifeboats, etc. His title as a British peer was The Right Honorable.
After an argument with his brother-in-law on the manner of the numbers of lifeboats being cut short he left Harland and Wolff, and ended his involvement in the designing of the Olympic class liners. The Olympic class liners would be the last ships that he would ever be involved with.