Alfonso d'Avalos d'Aquino, 6th Marquis of Pescara, 2nd Marquis of Vasto (1502 – 31 March 1546), was an Italian condottiero of Aragonese origins, renowned for his service in favour of Charles V, Holy Roman Emperor and King of Spain.
He was born in Ischia, as the son of Inigo d'Avalos (1467–1503) and his wife, Laura Sanseverino (d. 1512). He was a cousin of Francesco Ferdinando I d'Ávalos, whose titles he inherited after 1525. He fought the French and the Venetians by his side. He fought at the Battle of Pavia (1525). During the period 1526-1528, he fought under Hugo of Moncada, being captured on 28 April 1528 by the Genoese captain Filippino Doria at the Capo d'Orso.
In July 1535, he served as Imperial lieutenant during the reconquest of the city of Tunis in North Africa. The failure of the third war against France trying to invade Provence, and the death of the first Governor of the Duchy of Milan, Antonio de Leyva, prompted him in 1538 to accept the nomination as governor, replacing Marino Caracciolo, the second governor, becoming some sort of protector of literary and musical people . Wars with the French and North Italians ended for a while with the Treaty of Crespy (1544). He also became a Knight in the Order of the Golden Fleece. He later represented Emperor Charles V as an ambassador, in 1538, on the succession to the new Doge of the Republic of Venice, Pietro Lando.
He commanded the Imperial army in Italy during the Italian War of 1542 and was defeated by the French at the Battle of Ceresole. However, in the Battle of Serravalle on 2 June 1544, an aftermath of the Italian War of 1542, he managed to defeat a force of freshly raised Italian mercenaries in French service, commanded by Pietro Strozzi and Giovanni Francesco Orsini, count of Pitigliano.
On 26 November 1523, he married Maria d'Aragona (1503–1568), daughter of Duke Ferdinando di Montalto and his wife, Catalina Cardona. She was a paternal granddaughter of King Ferdinand I of Naples. They had 5 children: