This work has focused on investigating the comparative performance of the conventional type of offshore jacket substructure and a modified twisted-tripod jacket type (MTJ) under static and dynamic loading environment. Conventional four-legged and four number of MTJ structures, with a finite number of leg twisting angles from 0° to 90°, for supporting 5 MW NREL wind turbine were analysed for a selected site. In order to compare performance under dynamic loading, the dimensions of the structures were designed iteratively using static stress analysis to ensure that all structures had a similar level of load-carrying capability. Static analyses were performed using SACS v8 and models were imported to SAP-2000 for dynamic response spectrum analyses. The results obtained here reveal that, in addition to savings in material costs, the modified twisted-tripod jacket performs more efficiently than conventional four-legged jackets. This study has established a framework of procedure for simplified analysis of wind turbine jackets under dynamic loading environment. © Springer Nature Switzerland AG 2020.