Coupling device for hydraulically and mechanically coupling a fuel injector to a fuel rail of a combustion engine, the coupling device having a fuel injector cup having a central longitudinal axis and being designed to be hydraulically coupled to the rail and to engage a fuel inlet portion of the injector, a first ring element being fixedly coupled to the cup, a second ring element being fixedly coupled to the injector, and a shell element with a first and second shell part. The first shell part is fixedly coupled to the second shell part. The first and second ring elements are axially arranged between the first and second shell part. The shell element is designed and arranged in a way that the first and second ring element are in engagement with the shell element to retain the injector in the cup in direction of the central longitudinal axis.