Marie Jeanette Wässelius (23 August 1784 – 5 December 1853) was a Swedish opera singer. She is referred to as the leading prima donna of the Royal Swedish Opera in the early 19th-century. She was a Hovsångare (1815) as well as an associé of the Royal Swedish Academy of Music (1817). She is also known as Mamsell Wässelia or only Wässelia.