Marcus Kevin O'Riordan (born 25 January 1998) is an English professional cricketer who plays for Kent County Cricket Club.
O'Riordan was born at Pembury in Kent and was educated at Tonbridge School where he played in the school cricket XI. He signed his first professional contract in August 2019 and made his debut for Kent later the same month in a 2019 t20 Blast match against Surrey at Canterbury. He made his first-class debut for Kent in a County Championship match against Nottinghamshire at Nottingham on 10 September 2019.