Titus van Rijn (Amsterdam 22 September 1641 - 1668) was the fourth and only surviving child of Rembrandt Harmenszoon van Rijn and Saskia van Uylenburgh. Titus is best known as a figure or model in his father's paintings and studies.
After Rembrandt's bankruptcy in 1656, Titus and his stepmother Hendrickje Stoffels were named as in charge of Rembrandt's affairs and an art-dealership began, specializing in Rembrandt's work. Titus made a will aged 15 at his father's insistence, making his father sole heir.
Titus in 1668 married Magdalena van Loo (1641-1669). Her father was Jan van Loo, silversmith and brother of Gerrit van Loo, his uncle, a lawyer in Het Bildt. The couple lived at Magdalena's mother's house on the Singel. They had one child: Titia (1669-1715).
Titus van Rijn died in 1668 and was buried in the Westerkerk in Amsterdam. His wife, mother-in-law and father all died a year later.