Diyosezi Gatolika ya Nyundo ni agace ka kiliziya cyangwa Diyosezi ya Kiliziya Gatolika ya Roma mu Rwanda, ifite icyicaro ku Nyundo . Yashinzwe ku wa 14 Gashyantare 1952 nka Vikariyati y'Ubutumwa ya Nyundo na Papa Piyo wa XII, imwe mu zigize Vikariyati y'u Rwanda . Yashyizwe ku rwego rwa diyosezi ku wa 10 Ugushyingo 1959 na Papa Yohani XXIII . Iyi Diyosezi ni imwe mu zigize Akarere k'Ubutumwa ka Arikidiyosezi ya Kigali .
Umwepiskopi wa Nyundo uriho ubu ni Anaclet Mwumvaneza .