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 can also include the surrounding countryside, had a population of around 930 in 2005.The Dutch blues band Cuby + Blizzards was founded in Grolloo.