| Nakagawa Masaharu | |
| Native Name Lang: | ja |
| Office: | Minister of the Environment |
| Primeminister: | Shinzo Abe |
| Term Start: | 2 October 2018 |
| Term End: | 11 September 2019 |
| Predecessor: | Koichi Yamamoto |
| Successor: | Yoshiaki Harada |
| Office1: | Member of the House of Councillors |
| Constituency1: | Tokyo at-large |
| Term Start1: | 12 July 2004 |
| Term End1: | 25 July 2022 |
| Predecessor1: | Toshio Ogawa |
| Successor1: | Toshiko Takeya |
| Birth Date: | 22 February 1947 |
| Birth Place: | Meguro, Tokyo, Japan |
| Party: | Liberal Democratic |
| Alma Mater: | University of Tokyo |
is a Japanese politician of the Liberal Democratic Party, a member of the House of Councillors in the Diet (national legislature). A native of Meguro, Tokyo and graduate of the University of Tokyo, he worked at the Ministry of Finance from 1969 until 2001. He was elected to the House of Councillors for the first time in 2004.