Stallarholmen is a locality situated in Strängnäs Municipality, Södermanland County, Sweden with 1,623 inhabitants in 2010.

An article in Strengnäs Tidning from 1927 says the word "holme" refers to the isthmus that juts out from the mainland.

Another suggested etymology relates to King Charles XI of Sweden stabling his horses and exchanging carriages in Stallarholmen during his regular trips to Kungsör.

However, Charles XI was king in the late 17th century, while there is reference to the name Stallarholmen in the letters of Gustav Vasa from the 1540s and 1550s, making this etymology somewhat dubious.

This festival, which features Viking style entertainers, craftsmen, drama and games attracts thousands of visitors each year.