House of the Dragon and its predecessor, Game of Thrones, are set in a fantasy world where dragons are real, can be ridden, and are used as weapons of war. At least a few protagonists in the original series and most of those in the prequel show belong to House Targaryen, the only existing family of dragon riders. Naturally, there is much interest in a ranking of all the Targaryen dragons from largest to smallest.

Here is a ranking of all the dragons.

The chart below goes beyond the shows and includes dragons from George R. R. Martin's books. The Targaryens were originally one of the 40 noble houses of dragonlords of the Valyrian Freehold. After one of its members, Daenys the Dreamer, had a dream about the Doom of Valyria, they moved to Dragonstone permanently, taking what they could with them, including the dragons. The Doom and its subsequent events left them as the only surviving family of dragonriders in the world of Martin's A Song of Ice and Fire.

In the books, Balerion had four recorded riders: Aegon I, Maegon I, Aerea Targaryen, and Viserys I. However, it's safe to assume he had other riders prior to the Conquest. A prop history book for House of the Dragon noted that Daenys the Dreamer claimed Balerion when he was no bigger than a horse, effectively making this event part of TV canon. Whether or not this is also book canon is unknown.