Articular cartilage possesses unique structure and composition giving rise to unusual mechanical behavior. Typically, it is a structurally graded material that displays variation in mechanical properties along the depth. In this communication, the geometrical probability approach has been used for predicting the in-plane Poisson’s ratio in the surface and middle zones of articular cartilage. The presented model has formulated a relationship between the Poisson’s ratio and collagen fibril alignment. A comparison has been made between the theoretical and experimental findings of Poisson’s ratio in the surface and middle zones of human patella cartilage, as obtained from the literature.