Francisco Castillo Nájera (25 November 1886 in Durango, Dgo.
– 20 December 1954 in Mexico City) was a Mexican diplomat and politician.
He was president of the Assembly of League of Nations from 1934 to 1935, ambassador to China and the United States, also as the Dean of the Diplomatic Corps in the last year of his tenure, 1945, and Secretary of Foreign Affairs from 1945 to 1946.