Tenby's town walls are a Grade I-listed medieval defensive structure around the town of Tenby in Pembrokeshire. They are assessed as one of the most important surviving medieval city walls in Britain. The walls were built in the 13th century by the Earls of Pembroke and improved in the 1450s. They were last known to have been repaired in 1588 and have declined thereafter. Most of the town's gates were demolished beginning in the 18th century and only one survives.