Keiko Nagaoka (?? ??, Nagaoka Keiko, born December 8, 1953) is a Japanese politician serving in the House of Representatives in the Diet (national legislature) as a member of the Liberal Democratic Party.
A native of Tokyo and graduate of Gakushuin University she was elected for the first time in 2005.
Her husband was politician Yoji Nagaoka, who committed suicide on August 1, 2005.