Bass River is an estuary and village in South Yarmouth, Massachusetts, United States.

At its widest and most southerly point, it opens to and meets Nantucket Sound.

West Dennis beach has become a popular site for kite boarding in the past few years.

The right side of the river, which is referred to as the 'Old Field Channel', goes towards West Dennis and the Fingers development.

After the marina, the river goes under the Route 28 bridge and winds five more miles deep into the cape.