Disclosed are various exemplary embodiments of a retainer system for a ground engaging tool. In one exemplary embodiment, the retainer system may include a lock having a lock rotation axis and including an outer surface extending about the lock rotation axis. The retainer system may also include a retainer bushing including an inner surface extending about the lock rotation axis, where the inner surface is configured to rotatably receive the outer surface of the lock. The outer surface of the lock and the inner surface of the retainer bushing may be aligned substantially parallel to the lock rotation axis.