Keishi Nagatsuka (長塚圭史, Nagatsuka Keishi, born 9 May 1975 in Tokyo, Japan) is a Japanese actor and writer, known for Shûkan Maki Yôko (2008), Get Up! (2003) and Riarizumu no yado (2003). He is active in theater, TV, and movie.

He has been married to Takako Tokiwa since October 20, 2009. He and Tokiwa both appears in Nobuhiko Ôbayashi's Hanagatami (2017).

His father is actor Kyōzō Nagatsuka.