The primary cause of joint slip is the construction clearance between the bolt shank and the bolt hole at assembly. Slippage corresponds to the relative displacement of a bolted joint under loads. To the best of the authors’ knowledge, slippage models have not been verified by experimental studies. In fact, slippage causes an increase in the displacement of the tower. On the other hand, wind turbines are subjected to cyclic loading. Ignoring the effects of cyclic loads in wind turbine analyses can cause incorrect estimation of wind turbine behavior. In addition, up to now no accurate model has been obtained to investigate joint slip effects in lattice towers and probe all of the effective parameters in order to accurately predict joint slip. In this study, the behavior of such joints is extensively studied by incorporating 51 joint tests. The authors generated joint slip data and different types of equal length angles. Bolt diameter and bolt arrangements are investigated and additional load-deformation curves are presented. This study can be useful to help in designing wind turbine towers with a higher level of accuracy and safety.