Anecdotes

Due to main actor Masaki Suda's increasing prolific popularity in Japan, it has become difficult to re-hire Suda for reprisals following W's end. As such, the actor Kiriyama is often the sole representative of Double to appear in subsequent appearances such as films or crossovers, while Suda's role being filled often with archival recordings or replacements. Kamen Rider Double still appears in scenes or films where Kiriyama is not involved.

The main actor Renn Kiriyama had previously auditioned for Kamen Rider Kabuto, Kamen Rider Den-O, Kamen Rider Kiva, and Kamen Rider Decade, before failing them. When he was ultimately cast as Shotaro, he cried tears of joy.

This series acts as a huge callback to Shotaro Ishinomori and the original Kamen Rider. Shotaro Hidari's first name. Kamen Rider W being the first green and black Main Rider since the Showa Era, colors used in most Showa Kamen Riders suit. And Kamen Rider Skull referring to Skull Man.

Despite being the fourth tokusatsu show to feature a character with two halves being different colors (the other three being Android Kikaider, Kikaider 01, and Metalder), this is the first show to utilize two heroes using the same body to fight.

Philip was named by Sokichi Narumi after the fictional detective Philip Marlowe.