Takashi Nagai (?? ?, Nagai Takashi, 3 February 1908, Matsue – 1 May 1951, Nagasaki) was a Catholic physician specializing in radiology, an author, and a survivor of the atomic bombing of Nagasaki.
His subsequent life of prayer and service earned him the affectionate title "saint of Urakami," and he has subsequently been honoured with the title of Servant of God, the first step towards Catholic sainthood.