Shinjiro Koizumi (?? ???, Koizumi Shinjiro, born 14 April 1981) is a Japanese politician who is currently serving as Minister of the Environment and a member of the House of Representatives of the Liberal Democratic Party.
He is the second son of 56th Japanese Prime Minister Junichiro Koizumi and younger brother of actor Kotaro Koizumi.
He enjoys popularity among both the Japanese public and younger LDP lawmakers, and is often viewed as a future candidate for Prime Minister of Japan.
Koizumi did a stint as a researcher at Washington-based think tank Center for Strategic and International Studies, while also active as Young Leader of the Pacific Forum CSIS.
He served as his father's political secretary.
He was elected to the lower house in 2009 after his father's retirement.
Koizumi has served as parliamentary vice-minister for reconstruction of the northeast region of Japan that was devastated by the March 2011 tsunami and nuclear disaster.
He has not, however, overtly backed his father's calls for Japan to abandon nuclear energy immediately.