Grand Harbour Lighthouse, Maritime navigation structure on Grand Manan Island, New Brunswick, Canada

Grand Harbour Lighthouse is a lighthouse on Grand Manan Island in New Brunswick featuring a square wooden tower with an attached keeper's residence. The structure was built as a compact, functional design suited to withstand the harsh coastal environment.

Islanders petitioned the New Brunswick government in 1878 for a light at Grand Harbour; it was built for $1,050 on land costing $150 and first lit on 10 October 1879. Storms damaged it repeatedly, prompting repairs in 1891 and a protective wall in 1898. It was decommissioned on 1 August 1963 after the Ingalls Head breakwater light opened, and collapsed in a gale on 19 November 2013.

The light keeper's family lived in a dwelling attached to the square wooden tower, and the last keeper left when the light was decommissioned on 1 August 1963. After the November 2013 gale destroyed the building, volunteers collected the surviving interior pieces and gave them to the Grand Manan Island museum.

The lighthouse no longer stands: it collapsed in a gale on 19 November 2013, so there is no tower to enter on Ross Island. The island is uninhabited and reached only by boat across Grand Harbour from Grand Manan; the crossing is tidal, so time any landing with the tide. Surviving interior pieces were collected by volunteers and given to the Grand Manan Museum.

Lighthouse Digest declared the tower "North America's most endangered lighthouse" in 1999. A rescue campaign in which the owner promised to match public donations within 60 days failed, and the structure collapsed in a gale on 19 November 2013. Volunteers gathered the surviving interior fittings and gave them to the Grand Manan Museum.