Dumsiai is a village in Jonava District Municipality, in Kaunas County, Lithuania. Dumsiai lies at 71 m above sea level. It has 33 inhabitants. The nearest city is Jonava, 5.2 km to the northwest. Among the landmarks around are Ninth Fort (29 km), M. K. Čiurlionis National Art Museum (29 km) and Pažaislis Monastery (24 km).