Kodaira (written: 小平) is a Japanese surname. Notable people with the surname include:
- Kunihiko Kodaira (小平 邦彦, 1915–1997), Japanese mathematician and Fields medalist
- Nao Kodaira (小平 奈緒, born 1986), Japanese speed skater and Olympic gold medalist
- Tadamasa Kodaira (小平 忠正, born 1942), Japanese politician
- Yoshinao Kodaira (小平 好直, 1918–2008), Japanese World War II flying ace
- Yoshio Kodaira (小平 義雄, 1905–1949), Japanese serial killer
- Yūki Kodaira (小平 有希, born 1981), Japanese voice actress