This paper is an attempt to think through Derrida's newly discovered Geschlecht III, the third and missing installment of Derrida's four part series on Heidegger and Geschlecht. I argue that Derrida's reading of Heidegger in Geschlecht III needs to be situated within the philosophico-political context of Derrida's 1984-85 seminar-given under the general title Philosophical Nationality and Nationalism-from which Geschlecht III is extracted. In the first part of the paper, I reconstruct Derrida's general problematic of national-humanism as he lays it out in the opening sessions of the seminar, before arriving at his reading of Heidegger, who will be part of "a sequence of German national-philosophism," as Derrida calls it. In the second part, the paper turns explicitly to Geschlecht III where, as I show, Derrida's thoroughgoing denunciation of a national-humanism in Heidegger becomes all the more telling when seen through the theoretical matrix of the seminar.