Zn-Al-Mg-coatings applied to steel sheet by using continuous hot dip galvanizing lines show increased corrosion resistance compared to classic zinc layers. The cracking behaviour during deformation is different to the standard coating systems, and depends on the content of the alloying elements. The aim of this work was the investigation of the micromechanics of the cracking development. A quantification of the cracking morphology depending on the deformation levels was carried out using stepwise stretching tests of samples produced by a hot dip galvanizing simulator. This enabled the determination of the influences of layer thickness and properties of the steel substrate. An estimation of the mechanical properties of the coating could be achieved by microhardness-measurements, the interfacial layer between substrate and coating was analysed using transmission electron microscopy. Finite element simulations enabled an illustration of the basic micromechanic processes of cracking formation and propagation. Possibilities for a specific manipulation of the morphology of the microcracks could be indicated.