Theodahad, also known as Thiudahad (Latin: Flavius Theodahatus Rex, Theodahadus, Theodatus; Gothic: 𐌸𐌹𐌿𐌳𐌰𐌷𐌰𐌸𐌿𐍃, Thiudahathus; born c. 480 AD in Tauresium – died 536) was the King of the Ostrogoths from 534 to 536 and a nephew of Theodoric the Great through his sister Amalafrida.
He might have arrived in Italy with Theodoric and was an elderly man at the time of his succession. Massimilliano Vitiello states the name "Theodahad" is a compound of 'people' and 'conflict'.
He arrested Amalaswintha, queen of the Ostrogoths from 526 to 534, and imprisoned her on an island in Lake Bolsena.
Political instability within the Ostrogothic kingdom served as a pretext to Byzantine general Belisarius to intervene in Sicily and Italy, at the service of the Emperor Justinian, causing the Gothic Wars.
Witiges ordered him killed, and succeeded him as king.
Theodahad had at least two children with a woman named Gudeliva: Theodegisclus and Theodenantha.
He was also notable for his dedicated adoration for Neoplatonic philosophy and poetry over martial prowess. His focus on erudition instead of bellicosity, in a time when Italy was relatively consumed by turmoil both foreign and domestic, is claimed to be a reason for his downfall.
Thiudehad appears as a character in the time travel novel Lest Darkness Fall, by L. Sprague de Camp.