Philippa Boyens, MNZM, is a New Zealand screenwriter and producer who co-wrote the screenplay for Peter Jackson's films The Lord of the Rings series, King Kong, The Lovely Bones, and the three-part film The Hobbit, all with Jackson and Fran Walsh.

She, Jackson and Walsh won the Academy Award for Best Adapted Screenplay for The Lord of the Rings: The Return of the King at the 76th Academy Awards in 2004. She was also co-producer in every one of Jackson's films since King Kong, and in District 9. Prior to screenwriting, Boyens worked in theater as a playwright, teacher, producer and editor. She also spent time as director of the New Zealand Writers Guild.

Boyens was a part-time student at the University of Auckland, graduating with a BA in English and History in 1994. She received a Distinguished Alumni Award from the university in 2006.

She has three children, daughter Phoebe Gittins and son Calum Gittins (both with actor Paul Gittins), and a second son, Isaac Miller. Phoebe appeared as a Hobbit in The Lord of the Rings: The Fellowship of the Ring, one of George Harvey's victims in The Lovely Bones, and a wench in the Prancing Pony in The Hobbit: The Desolation of Smaug; Calum appeared as Haleth in The Lord of the Rings: The Two Towers.; and Isaac appeared as a young Hobbit in a flashback of the Old Took's party in the extended edition of The Hobbit: An Unexpected Journey.