Tarbell Brook is a 10.1-mile-long (16.3 km) stream located in southwestern New Hampshire and northern Massachusetts in the United States. It is a tributary of the Millers River, itself a tributary of the Connecticut River, which flows to Long Island Sound. Tarbell Brook rises in the western part of Rindge, New Hampshire, at the outlet of Pearly Lake, and flows south to the Damon Reservoirs. The brook then passes into Winchendon, Massachusetts, reaching the Millers River approximately 2 miles (3 km) west of the town center.