Vantaanjoki () is a long river in Southern Finland. The river starts from the lake in Hausjärvi and flows into the Gulf of Finland at ' in Helsinki. One of the tributaries of Vantaanjoki is Keravanjoki that flows through the town of Kerava north of Helsinki.
The country's capital, Helsinki, uses water from Vantaanjoki as its backup water supply if the Päijänne Water Tunnel needs to be repaired.
The Helsinki-based energy company Helsingin Energia has a working power station museum located at the mouth of Vantaanjoki. The Hydropower Plant produces an average of 500 MWh annually.