Percy Jackson: Sea of Monsters (also known as Percy Jackson & the Olympians: The Sea of Monsters and Percy Jackson and the Sea of Monsters) is a 2013 fantasy adventure film directed by Thor Freudenthal from a screenplay by Marc Guggenheim, based on the 2006 novel The Sea of Monsters by Rick Riordan. The sequel to Percy Jackson & the Olympians: The Lightning Thief (2010), it is the second and final installment in the Percy Jackson film series.

The film continues the adventures of Percy Jackson (Logan Lerman) and his friends as they journey to the eponymous Sea of Monsters to retrieve the Golden Fleece in order to save the tree barrier that protects their home. Lerman, Brandon T. Jackson, Alexandra Daddario, and Jake Abel reprise their roles from the previous film, while Nathan Fillion and Anthony Head replace Dylan Neal and Pierce Brosnan, respectively. New additions to the cast include Leven Rambin, Douglas Smith, and Stanley Tucci.

Percy Jackson: Sea of Monsters was released theatrically in the United States on August 7, 2013, by 20th Century Fox. The film received mixed-to-unfavourable reviews from critics, with praise for its visuals and action, but criticism for its plot and characters. It grossed $200.9 million worldwide against a production budget of $90 million. A sequel based on The Titan's Curse was planned, but never produced. Following the acquisition of 21st Century Fox by Disney in 2019, Disney consequently gained the rights to the Percy Jackson novels, upon which Riordan pitched a television adaptation that debuted on Disney+ in 2023.