Castlevania is an American adult animated dark fantasy action television series created and written by Warren Ellis for Netflix, and is produced by Frederator Studios's Kevin Kolde and Fred Seibert and Shankar Animation's Adi Shankar. Based on the Japanese video game series of the same name by Konami, the first two seasons adapt the 1989 entry Castlevania III: Dracula's Curse and follow Trevor Belmont, Alucard and Sypha Belnades as they defend the nation of Wallachia from Dracula and his minions. Additionally, characters and elements from the 2005 entry Castlevania: Curse of Darkness are featured beginning in the second season, and Alucard's backstory is drawn from the 1997 entry Castlevania: Symphony of the Night. The art style is heavily influenced by Japanese animation and Ayami Kojima's artwork.

Castlevania was originally planned as a film, developed by producer Kevin Kolde and his company Project 51. He joined Frederator Studios in 2005, and founder Fred Seibert agreed to produce the project there. They contracted a script with writer Warren Ellis in 2007. The project entered development hell until about 2015, and it was picked up by streaming service Netflix. Powerhouse Animation Studios joined the team and production commenced. The production team includes staff members who worked in the Japanese anime industry.

The series premiered on Netflix on July 7, 2017, and was renewed for an expanded second season of eight episodes on the same day; the second season premiered on October 26, 2018. A ten-episode third season was greenlit by Netflix and released on March 5, 2020. The series ended with the release of its fourth season on May 13, 2021. The series received critical acclaim, with praise for its visuals, animation, voice acting, action sequences, characterization, themes, and writing, although the pacing, particularly of the third and fourth seasons, garnered a polarized response.

A follow-up series in the Castlevania setting, Castlevania: Nocturne, premiered on Netflix on September 28, 2023. The series focuses on Richter Belmont, a descendant of Trevor and Sypha, and Maria Renard during the French Revolution, with James Callis reprising his role as Alucard.