Apparatus and methods for positioning and securing anchors are disclosed herein. The anchors are adapted to be delivered and implanted into or upon tissue, particularly tissue within the gastrointestinal system of a patient. The anchor is adapted to slide uni-directionally over suture such that a tissue plication may be cinched between anchors. A locking mechanism, either within the anchor itself or positioned proximally of the anchor, may allow for the uni-directional translation of the anchor while enabling the anchor to be locked onto the suture if the anchor is pulled, pushed, or otherwise urged in the opposite direction along the suture. This uni-directional anchor locking mechanism facilitates cinching of the tissue plication between the anchors, and it may be utilized in one or several anchors in cinching a tissue fold.