Systems and methods for reverse flow detection for a dual fuel engine are disclosed. The engine may include an intake manifold, a liquid fuel supply line and a gaseous fuel supply line, the gaseous fuel supply line including a gaseous fuel supply and a gaseous fuel rail. The method may include: receiving sensed values of gaseous fuel supply pressure, intake manifold pressure, and gaseous fuel rail pressure; determining a threshold value based on the sensed value of gaseous fuel supply pressure; determining a reverse flow in the gaseous fuel supply line based on the sensed values of gaseous fuel supply pressure and gas rail pressure and the determined threshold value; and outputting an indication of reverse flow in response to the determination of reverse flow.