Romualda Baudouin de Courtenay, née Bagnicka (born November 17, 1857, in Aleksandrówka near Kyiv, died February 26, 1935, in Warsaw) was a Polish historian, specialist in Polish-Russian affairs, and author of books, diaries and journalistic articles. She was married to noted linguist Jan Niecisław Baudouin de Courtenay.