Swedish origin
Source-reportedFrom the Swedish royal name Gustaf, Gustav. The town (formerly named Kivimaa) was renamed to its current name in 1897 to match the name of its church, which had been named after Gustav III (the king of Sweden and still Finland at the time, in 1782).
Sources for this account (2)
- Wiktionary: KustaviCC-BY-SA-4.0 · retrieved 2026-10-15
- Greek Wiktionary: KustaviCC-BY-SA-4.0 · retrieved 2026-10-15

