Brianna Hildebrand (born August 14, 1996) is an American actress. She is best known for appearing as Negasonic Teenage Warhead in the films Deadpool (2016), Deadpool 2 (2018), and Deadpool & Wolverine (2024). She is also known for appearing in the web series Annie Undocumented, and as the character Aurora in the Netflix show Lucifer. She also portrayed Elodie Davis in the show Trinkets.

Brianna Hildebrand was born in College Station, Texas.

Hildebrand appeared in the web series Annie Undocumented, named best web series at the 2014 New York TV Festival. The series was created by Daniel Hsia, Elaine Low and Brian Yang.

Hildebrand was cast as the superhero Negasonic Teenage Warhead in the film Deadpool on March 30, 2015. The film was shot in Vancouver in April 2015, and released on February 12, 2016. She reprised the role in the sequel in 2018. She was also cast as Sasha in First Girl I Loved, starring opposite Dylan Gelula and Mateo Arias.

In July 2017, Hildebrand was added to the main cast for season two of The Exorcist. In December 2020, Hildebrand was added to the cast of Lucifer for its final season.

Hildebrand is openly queer. She is a vocal advocate for LGBTQ+ rights and has spoken about her experiences as a queer woman.