James Paul Marsden (born September 18, 1973) is an American actor. He began his acting career as a guest star on the television shows Saved by the Bell: The New Class (1993), Touched by an Angel (1995), and Party of Five (1995). Marsden gained fame for his portrayal of Cyclops in the X-Men film series (2000–2014) and his roles in the films The Notebook (2004), Superman Returns (2006), Hairspray (2007), Enchanted (2007), 27 Dresses (2008), and Anchorman 2: The Legend Continues (2013). He portrayed John F. Kennedy in the drama film The Butler (2013) and Tom Wachowski in the Sonic the Hedgehog film series (2020–present).

Marsden starred in the HBO science fiction series Westworld from 2016 to 2022 and in the Netflix black comedy series Dead to Me from 2019 to 2022, for which he received a nomination for a Critics' Choice Television Award. He played guest roles in the  Modern Family (2011) and 30 Rock (2012–2013) sitcoms. He starred as a fictionalized version of himself in the mockumentary series Jury Duty (2023), for which he received nominations for a Golden Globe Award and a Primetime Emmy Award. Marsden has since starred in the Hulu thriller series Paradise (2025). He is returning as Cyclops in the upcoming movie Avengers Doomsday.