Originally a patronymic form Gustavs + -son "son of Gustav". The v-sound was spelled with f in the end of a word prior to 1906 therefor Gustaf (pronounced Gustav) became Gustav when the reform took place. Although with names the f-spelling remains to this day to a quite big extent and the variant Gustafsson is still very common.
Gustavsson c (genitive Gustavssons)
- A common surname.