A surgical access assembly for positioning within an opening in tissue including an outer member positionable outside a patient and defining an opening therein to receive a surgical instrument. The outer member has a first portion and a second portion wherein at least one of the first and second portions is movable with respect to the other portion. The assembly also includes an inner member positionable within a patient and a flexible member extending between the inner member and outer member, wherein movement of one of the first and second portions of the outer member adjusts tension on the flexible member to retract tissue. A locking mechanism locks the outer member in a plurality of select expanded positions. The locking mechanism includes first engagement structure on the first portion engageable with the second portion and a slidable member movable to a locking position to retain the first and second portions in the select expanded position.