This paper presents an analytical approach to predict the mechanical behavior of different types of screw lap shear joints using a spring-mass model. The spring-mass model captures the axial, bending, bearing, and shear stiffnesses of the components and their masses at the joint. The springs in the model represent the stiffness arising from each of these modes of deformation. We derive the expressions of the individual stiffnesses analytically and use the spring-mass model to obtain the overall joint stiffness. We show that this joint stiffness accurately predicts the experimentally observed mechanics of counter-bore and countersink screw lap joints. The experimental validation is carried out in nine different joint configurations. The analytical model is also validated with the aid of linear finite element analysis. Furthermore, the influence of individual stiffness components on the overall joint behavior is studied by varying the thickness and width of the plates. © 2022 Taylor & Francis Group, LLC.