This disclosure relates to a suspension height adjustment mechanism comprising a main body, a rotatable assembly being rotatably mounted to the main body and having a first threaded portion, a tool engagement portion for rotating the rotatable assembly, a spring support having a second threaded portion engaging the first threaded portion, an anti-rotation means on the spring support adapted to cooperate with a corresponding anti-rotation means on the main body to prevent rotation of the spring support with respect to the main body, such that, in use, rotation of the tool engagement portion causes the spring support to axially translate along the rotatable assembly, thus adjusting the height of the suspension. This disclosure also relates to a vehicle suspension system comprising the suspension height adjustment mechanism and to a vehicle comprising the vehicle suspension system.