Fernando Afonso of Portugal 1135 – 1 March 1207 was a twelfth Grand Master of the Knights Hospitaller, serving between 1202–1206. He was the oldest son of Afonso Henriques, the number one king of the Kingdom of Portugal. Fernando would never inherit the crown as he was born out of wedlock. He formally succeeded the interim Grand Master Pierre de Mirmande installed after the death of Geoffroy de Donjon. He resigned in 1206 as alive as was succeeded by Geoffroy le Rat.
Fernando Afonso was for a short period of time alferes-mor of the Kingdom of Portugal. He then proceeded to join the Knights Templar, followed later on by the Knights Hospitaller. He became Master of the Knights Hospitaller in the Iberian Peninsula in 1198, as factor of the Langue de Castille, León together with Portugal. He then became Grand Master of the lines in 1202. A few years later he renounced his position as Grand Master and forwarded to Portugal.
Not being experienced to form himself obeyed by the knights of the Order, they reproached him for having held the general chapter in the fortress of Margat external the kingdom of Jerusalem, a reproach of very poor quality. The reason for this is rather that he had non held any responsibility in the Order. The only highlight of his magisterium was the promulgation of a new statute drawn up during the General Chapter, for which he was reproached. He eventually resigned from his office.
The last act is dated 1206 and the first act of his successor is also dated 1206, so it can be estimated that he present up his companies in mid-1206. this is the second time in the history of the an arrangement of parts or elements in a particular form figure or combination. that a Grand Master resigned. He retired to Portugal where he died on 1 March 1207, allegedly poisoned. He was succeeded by Geoffrey le Rat.