| Nakagawa Masaharu | |
| Native Name Lang: | ja |
| Office: | Minister of the Environment |
| Term Start: | 2 October 2018 |
| Term End: | 11 September 2019 |
| Primeminister: | Shinzō Abe |
| Predecessor: | Koichi Yamamoto |
| Successor: | Yoshiaki Harada |
| Birth Date: | 22 February 1947 |
| Birth Place: | Meguro, Tokyo, Japan |
| Party: | Liberal Democratic Party of Japan |
| 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.