Modern engineering applications require materials with exceptional and distinctive mechanical properties. Biological composites possess excellent mechanical properties due to their hierarchical and staggered structure. A stair-wise staggered arrangement is an idealized structure based on biological composites such as bone and nacre. Here, the platelets are arranged in a stair-wise manner, in which the platelets in the succeeding rows are offset by a certain distance, for a specified number of rows, which is referred to as the period (n) of the model. In bio-inspired stair-wise staggered composites randomness could exist in their microstructural building elements and interface properties due to flaws in manufacturing. The influence of microstructural randomness has to be looked into since these variations could significantly affect the mechanical properties of bio-inspired composites. Although researchers have extensively explored the influence of microstructural randomness in regular staggered brick and mortar (BaM) composites, there remains a gap in the literature regarding its impact in stair-wise staggered BaM composites. The present study examines the influence of random platelet aspect ratio in the mechanical properties of stair-wise staggered composites. 2D finite element models with stair-wise staggered arrangement are made assuming the platelets to be elastic. The interface delamination is modeled using cohesive zone material model (CZM) in which fracture mechanism is brought into use by following traction separation relation at the interface. The models are used to find the variations in stress distribution and failure pattern when randomness in the platelet aspect ratio is considered. The results show that randomness in platelet aspect ratio affects the stress distribution and failure pattern of stair-wise staggered composites.