A robotic carton unloader for automatic unloading of cartons from a carton pile. In various embodiments, a robotic carton unloader may comprise a mobile body, a movable robotic arm attached to the mobile body and comprising an end effector configured to unload a row of cartons in a side-by-side orientation from the carton pile, and a conveyor system mounted on the mobile body and configured to receive the row of cartons from the end effector in the side-by-side orientation. In various embodiments the conveyor system may comprise a front-end descrambler and a central descrambler coupled to the front-end descrambler. In various embodiments, the robotic arm may be configured to straddle at least a portion of the mobile body and at least a portion of the conveyor system such that the conveyor system conveys cartons from the carton pile through the robotic arm.