This report deals with the buckling behavior of spirally welded steel tubes. First, an existing analytical solution and the results of an extended experimental investigation are investigated. The imperfections measured during testing are investigated and classified, and methods are proposed to incorporate them into finite element models. Buckling analyses are carried out using finite element software, the resulting eigenmodes are characterized, and the response of tubes to various combinations of buckling modes is investigated. Next, the tubes themselves are modeled, incorporating these imperfections, full material models, and residual stresses. The results are compared to the results of the experimental program. Statistical analyses are also performed to investigate the accuracy of the models. Finally, parameter studies are carried out in order to investigate the effect that various parameters have on the response of the tubes, both in terms of critical curvature and maximum moment. The parameters are characterized based on their significance, and recommendations are made for future research.