Admiral of the Fleet Sir Alfred Phillipps Ryder KCB (27 June 1820 – 30 April 1888) was a Royal Navy officer.

He pursued the Nicaraguan commander, a Colonel Salas, for 30 miles up the San Juan River and captured the fort at Serapique.

Ryder became commanding officer of the frigate HMS Dauntless in which he saw action in the Black Sea and then took part in the Battle of Kinburn during the Crimean War.

[3] During the War Admiral Sir Charles Napier threatened to court-martial him for letting an enemy ship escape but the Admiralty refused to support this course of action.

[1] Ryder went on to be commanding officer of the second-rate HMS Hero in the Channel Squadron in January 1861 and then became Private secretary to Edward Seymour, 12th Duke of Somerset, First Lord of the Admiralty in November 1862 before becoming Controller of the Coastguard in 1863.

[9] Ryder retired in 1882 and became a trustee of the Church of England Purity Society, an organisation founded by Edward Benson, a former Archbishop of Canterbury.

Ryder wrote letters under the pen name of XYZ drawing attention to the plight of young female models and the practice of men and women studying them together.