In this contribution, the delamination behaviour in cross-ply glass fiber reinforced composites under static tensile loading is investigated numerically using both cohesive elements and contact cohesive surfaces in the commercial finite element software ABAQUS. The laminates studied contain predefined microcracks in the embedded 90° ply, which serve as the source of delamination. Particular attention is paid to the connection of the pre-existing matrix crack tips to the cohesive zone in the [0/90] interfaces, which have a strong influence on delamination initiation and growth. The presented analysis includes different modelling approaches of microcrack-induced delamination (MCID), which are compared and critically discussed. In this relation, the different modelling approaches partly show a strong influence on the simulation results. The static MCID model can be converted to a fatigue MCID model by using a cyclic cohesive zone model.