A child restraint system is configured to secure a child in a seat. The child restraint system includes a harness configured to extend across the child. The harness includes at least one connector. The child restraint system includes at least one anchorage configured to releasably connect to the connectors. The at least one anchorage extends through at least one slot in the seat. In some embodiments, the child restraint system includes an adjustment mechanism coupled to the at least one anchorage and configured to adjust a position of the at least one anchorage relative to the seat. The adjustment mechanism has a locked configuration in which the adjustment mechanism is prevented from moving along the at least one slot and an unlocked configuration in which the adjustment mechanism is movable along the at least one slot.