A mixing device for introducing gaseous fuel and recirculated exhaust gas into an intake passage of an engine, the mixing device including a body, an annular channel, the body defining a fuel inlet opening, and a plurality of gaseous fuel injectors fluidly coupled to the fuel inlet opening such that gaseous fuel from the plurality of gaseous fuel injectors is conveyed into the annular channel through the fuel inlet opening. The mixing device further includes a diffuser at a position of the annular channel to diffuse gaseous fuel from the annular channel into the intake airflow in the intake passage, an exhaust gas recirculation (EGR) inlet opening defined by the body and in fluid communication with the intake passage, and an exhaust gas recirculation supply pipe coupled to the EGR inlet opening and configured to direct recirculated exhaust gas from the engine into the intake passage.