A housing for an armature of a fuel injector, a fuel injector and a fuel injection system are disclosed. The armature housing includes a first cylindrical portion for slidably accommodating the armature pin. The first cylindrical portion has a minimum inner diameter that is closely matched to the maximum outer diameter of the armature pin. A second cylindrical portion of the armature housing accommodates the armature. The second cylindrical portion has an inner minimum diameter that is closely matched to the maximum outer diameter of the armature. The disclosed armature housing provides more reliable and more consistent movement of the armature.