Lesnes Abbey /ˈlɛsnɪs/ is a former abbey, now ruined, in Abbey Wood, in the London Borough of Bexley, southeast London, England. It is a scheduled monument and the abbey's ruins are listed at Grade II by Historic England. The adjacent Lesnes Abbey Woods are a Local Nature Reserve. Part of the wood is the Abbey Wood SSSI, a geological Site of Special Scientific Interest which is an important site for early Tertiary fossils.