Marquess of Fontes (in Portuguese Marquês de Fontes) was a Portuguese title of nobility, granted by a decree issued by King Afonso VI of Portugal on 2 January 1659, to D. Francisco de Sá e Menezes, 3rd Count of Penaguião.
On 24 June 1718, the 3rd Marquess of Fontes, Rodrigo Anes de Sá Almeida e Menezes, had his title changed, by King John V of Portugal, to Marquess of Abrantes, once he descended, by female line, from the prestigious Counts of Abrantes, an old line already extinct.