The effects due to an arbitrary location of the load point on the buckling and post-buckling behaviour of elastic thin-walled beams are investigated. The governing differential equations and the corresponding stiffness matrices are derived, based on the virtual work equation of linearized finite displacement. Numerical examples are given to investigate the behaviour of I, channel and zee shaped beams. Location of load point greatly affects the post-buckling behaviour as well as the buckling loads. Although zee and channel sections show a large reserve strength as compared with I-section, this reserve strength corresponds to fairly large stresses and displacements.