Marsh Harbour is a town in Abaco Islands, Bahamas, with a population of 6,283 as of 2012.

Marsh Harbour has the majority of services available in all of the Abacos, including a post office, bookstore, grocery stores, specialty shops, travel agencies, and laundries.

Visitors come to boat, swim or snorkel, and stay at one of the lodges located near Bay Street on the waterfront, though some adventurers reserve a day or two to kayak in the Marls on trips conducted by naturalist guides.

The Marls are an extensive region of pristine mangrove habitat and open shallows called "flats" that harbour a rich variety of wildlife and offer an important fisheries, for local sustenance and for sport.

In 2019, Marsh Harbour was directly impacted by category 5 Hurricane Dorian, severely damaging most structures and infrastructure in the city.