Blessed Francesc de Paula Castelló Aleu (19 April 1914 – 29 September 1936) was a Spanish Roman Catholic killed during the Spanish Civil War on false accusations of fascism.
Castelló was noted for his devout and outgoing nature in addition for his activism in Christian movements such as the Catholic Action; he had friends from these movements and in one met his fiancée though his death broke their soon-to-be union.
He worked as a chemist for a time prior to conscription into the armed services on the eve of the civil war.
His beatification was confirmed after Pope John Paul II – who beatified him on 11 March 2001 – acknowledged the fact that Castelló had been killed "in odium fidei" (in hatred of the faith).
He was beatified as part of the cause of 232 others.