Grolloo is a village in the Dutch province of Drenthe. It is a part of the municipality of Aa en Hunze, and lies about 11 km southeast of Assen. In 2001, the village of Grolloo had 541 inhabitants. The built-up area of the village was 0.27 km², and contained 203 residences.
The statistical area "Grolloo", which also can include the surrounding countryside, had a population of around 930 in 2005. The famous Dutch blues band Cuby + Blizzards was founded in Grolloo. There is a museum in the farm house where they began. There is also a statue of Harry Muskee (the band's lead singer) in the village.