János Wass (Hungarian pronunciation: [ˈjaːnoʃ ˈvɒʃ]), or "Prince" John (16th century), was an illegitimate son of the ill-fated King Louis II of Hungary and Bohemia, who would die aged 20 at the Battle of Mohács. His mother was Angelitha Wass, formerly a lady's maid of the king's mother Anne of Foix-Candale.

His and his mother's names appear in the sources of the Chamber in Pozsony (now Bratislava) as either János Wass, taking his mother's surname, or János Lanthos, meaning John the Bard. He was never officially recognized as the son of King Louis, but he styled himself a prince nevertheless. He received regular subsidy from the court of King Ferdinand I of Germany, who was his uncle by his wife, Queen Anna Jagiellon, the sister of King Louis II and then of King Maximilian II, who was his cousin. With this financial backing he bought a house in Pozsony, where he lived with family and eventually died.

He had a large family; there was a rumour that a daughter of his gave birth to 20 children, and he demanded extra financial backing for his daughter's wedding.

• Kubinyi, András: Törvénytelen gyermekek a magyar középkorban. Utódok, örökösök, fattyúk (Illegitimate Children in Medieval Hungary. Offsprings, Successors, Bastards), História 21, 20–22, 1999. URL: See External Links
• Takáts, Sándor: II. Lajos király fia (A Son of King Louis II Jagiellon), Századok (Periodical Centuries), 183–185, 1903.
• Tardy, Lajos: Rémmesék II. Lajos és „természetes” fia körül. (Blood-freezers about King Louis Jagiellon and his 'Natural' Son In Lajos Tardy: Kis magyar történetek (Short Hungarian Stories), Budapest, 40–53, 1986.

• Kubinyi, András: Törvénytelen gyermekek a magyar középkorban (Illegitimate Children in Medieval Hungary) – 20. February 2011.