Ichirō Ōkouchi (大河内 一楼, Ōkouchi Ichirō, born 28 March 1968) is a Japanese screenwriter and novelist. He is a graduate of Waseda University, School of Human Sciences. Ōkouchi is best known for collaborating with director Gorō Taniguchi for composing the story and script of the Sunrise original production, Code Geass: Lelouch of the Rebellion in 2006 and its sequel Code Geass: Lelouch of the Rebellion R2 in 2008.