Kamen Rider W , also called Kamen Rider Double, is a 2009–2010 Japanese tokusatsu drama, the eleventh series in the Heisei period run of the Kamen Rider Series and the twentieth overall. It premiered following the finale of Kamen Rider Decade on September 6, 2009, and aired alongside Samurai Sentai Shinkenger in TV Asahi's Super Hero Time programming block. Following Shinkenger's finale, it aired alongside Tensou Sentai Goseiger, until W concluded on August 29, 2010. The series is described as the "Heisei Kamen Rider 10th Anniversary Project: Fall Campaign" . In the first episode of Kamen Rider Fourze, W is revealed to be in the same continuity as the original Showa timeline, making it the first series to do so since Kamen Rider Agito. The series is notable for being the first installment in what's popularly viewed as Heisei era Kamen Rider's second phase by fans. A sequel manga series, Fuuto PI, began serialization in August 2017 and an anime adaptation began airing in August 2022.

The Kamen Rider Series , also known as Masked Rider Series, is a Japanese superhero media franchise consisting of tokusatsu television programs, films, manga, and anime, created by manga artist Shotaro Ishinomori. Kamen Rider media generally features a motorcycle-riding superhero with an insect motif who fights supervillains, often known as kaijin .