Riku Onda (恩田 陸, Onda Riku) is the professional name of Nanae Kumagai (熊谷 奈苗, Kumagai Nanae, born 1964), a Japanese writer. Onda has won the Yoshikawa Eiji Prize for New Writers, the Japan Booksellers' Award, the Mystery Writers of Japan Award for Best Novel, the Yamamoto Shūgorō Prize, and the Naoki Prize. Her work has been adapted for film and television.