Glack is a hamlet and townland in County Londonderry, Northern Ireland. It is 4 km south of Ballykelly, in a raised spot overlooking Lough Foyle. . In the 2001 Census it had a population of 183 people. It is situated within Causeway Coast and Glens district.
Glack is made up of three clusters of buildings. It has a primary school (St Finlough's, in neighbouring Sistrakeel townland) and a business called Paragon Tiles Ltd.