The following is a list of Japanese writers whose family name begins with the letter O

• Oda Sakunosuke (October 26, 1913 – January 10, 1947)
• Oe Kenzaburo (January 31, 1935 - March 3, 2023)
• Ogawa Yoko (born 1962)
• Ogiwara Seisensui (1884–1976)
• Oguri Mushitaro (March 14, 1901 – February 10, 1946)
• Okakura Kakuzo (December 26, 1862 – September 2, 1913)
• Okamoto Kanoko (March 1, 1889 – February 18, 1939)
• Okamoto Kido (October 15, 1872 – March 1, 1939)
• Omae Ao (born November 28, 1992)
• Ono Fuyumi (born 1960)
• Ono no Komachi (c. 825 – c. 900)
• Ooka Makoto (1931–2017)
• Ooka Shohei (March 6, 1909 – December 25, 1988)
• Orikuchi Shinobu (February 11, 1887 – September 3, 1953)
• Osanai Kaoru (July 26, 1881 – December 25, 1928)
• Oshikawa Shunro (March 21, 1876 – November 16, 1914)
• Ota Mizuho (1872–1963)
• Otomo no Yakamochi (c. 718 – 785)
• Ozaki Hosai (January 20, 1885 – April 7, 1926)
• Ozaki Kihachi (1892–1974)
• Ozaki Koyo (January 10, 1867 – October 30, 1903)