Rear Admiral Simon Paul Williams CB, CVO, KStJ (born 13 July 1960), is a retired senior Royal Navy officer who served as Naval Secretary, Assistant Chief of Naval Staff (Personnel) and Flag Officer (Maritime Reserves) from March 2015 to June 2018.

[1] Since 2025, Williams serves as Prior of St John in England.

[2] Born in 1960 at Bristol, Williams was educated at Kingsbridge School,[3] the City University London (BSc) and the Britannia Royal Naval College.

[4] Williams became Director of Naval Personnel Strategy at the Ministry of Defence in 2008,[3] Commodore of the Britannia Royal Naval College in March 2011[4] and then Defence Services Secretary[5] as well as Assistant Chief of the Defence Staff (Personnel and Training) in October 2012.

[7] Appointed Chancellor of the Priory of England and Islands of the Order of St John in 2023, Williams was promoted Prior of St John in 2025.