Kenji Yamaoka (山岡 賢次, Yamaoka Kenji, born April 25, 1943) is a former Japanese politician of the Democratic Party of Japan (DPJ), who served as a member of the House of Councillors and the House of Representatives in the Diet (national legislature).

He married the daughter of writer Sōhachi Yamaoka and was adopted into the family.

[1] In September 2011 he was appointed as chairman of the National Public Safety Commission, Minister of State for Consumer Affairs and Food Safety and Minister for the Abduction Issue.

in the cabinet of newly appointed Prime Minister Yoshihiko Noda.

[2][3] In December 2011 he was the subject of a censure motion from the opposition LDP for failing to declare receiving ¥450,000 from a health food company allegedly involved in a pyramid scheme in 2008, and ¥2.54 million from other organizations involved in pyramid schemes between 2005 and 2008.