Fukujirou Yokoi (横井福次郎) was a Japanese mangaka who is perhaps best known as a major inspiration to Osamu Tezuka (in addition to Leiji Matsumoto, Yoshiharu Tsuge, and Ryuuichi Yokoyama, among others). His classic series Fushigi na Kuni Puchar (sometimes unofficially localized into English as Puchar in Wonderland or Puchar in the Land of Marvels) is regarded by manga critics such as Kunio Hase as a leading work in the sci-fi manga of the US occupation era in Japan (1945-1952, Showa 20-27).

Often published in magazines such as Shounen Club and VAN, Yokoi wrote prolifically from 1946-1948, at one point amounting to 35 simultaneous serializations.

On December 5, 1948, Yokoi died of tuberculosis. The popular sequel to Fushigi na Kuni Puchar, Boukenji Puchar (sometimes unofficially localized into English as Adventure Boy Puchar or Puchar the Adventurer), was after Yokoi's death finished by Tetsuo Ogawa.

One of the few English-language writers to cover Yokoi in any capacity has been British manga historian Helen McCarthy, who wrote a short article on Yokoi in 2010.