The Mid-infrared ELT Imager and Spectrograph (METIS), which will be one of the first-light instruments on the Extremely Large Telescope (ELT), will be equipped with an Adaptive Optics (AO) system that will use a natural guide star as reference for the correction of the wavefront errors, introduced by the atmospheric turbulence. Even though this system will suffice for the achievement of the instrument’s primary science goals, it will not allow for observations of additional objects of interest, due to the limited sky coverage it offers. In order to increase the sky coverage of the instrument, a supplementary AO system, which will use a single laser guide star as reference, is planned to be added at a later stage. In the present thesis, a possible solution for the (opto)mechanical design of this laser-assisted AO system is provided, which ensures compliance with the predetermined mass, volume and budget limits.