Kyohei Sakaguchi (坂口 恭平, Sakaguchi Kyōhei, born 13 April 1978) is a Japanese artist and architect who was born in Kumamoto. He graduated from Waseda University's department of architecture in 2001. He is most known for his Zero Yen Project, which involves studying structures built at no cost, such as shanties made by the homeless. In 2013 his book, Build Your Own Independent Nation was published. In 2014, he wrote a novel, Genjitsu Dasshutsuron (Thesis on Escaping Reality). In 2020 his book Kurushii Toki wa Denwa Shite (Call Me When You're in Pain) was published.