Onni is of Finnish origin, derived from the word 'uni', meaning 'one'. It is often used as a given name for both boys and girls in Finland, but it can also be found in other countries. The name has gained popularity outside of Finland, with notable bearers including Onni Tommila, a Finnish actor known for his role in the "Big Game" film franchise.
The name Onni has seen fluctuations in popularity over the years, with peaks in recent times.