Bayham Old Abbey is an English Heritage property, situated near Lamberhurst, Kent, England. Founded c. 1207 through a combination of the failing Premonstratensian monasteries of Otham and Brockley, Bayham functioned as an abbey until its dissolution in the sixteenth century. The ruins were partially modified in the late eighteenth century, to provide a better landscape feature during landscaping of the new Bayham Abbey mansion park, and were donated to the state in 1961.