This work is aimed at quantifying the expected advantages and disadvantages of fuel systems for box-wing aircraft, with respect to fuel systems for conventional aircraft. For this, the Multi Model Generator has been extended with an aircraft type-agnostic fuel system module capable of generating preliminary fuel system geometries, assessing the system weight, and estimating the fuel flow for a mission comprised of a single cruise segment. It is found that the box-wing aircraft struggles to maintain within the flight envelope for ferry and maximum range missions, and that the difference in fuel consumption between fuel system designs is negligible. The most effective fuel system design has a mass of 291.59kg (0.23% of aircraft mass), connects the front and rear wing tanks through the connecting element, and features a forward trim tank with a capacity of 858kg (3.0% of total capacity). With this fuel system, the reference box-wing aircraft is stable for maximum payload missions, and unstable at the start of maximum range missions.