Dynamic behaviour often is a topic of concern in the design of pedestrian bridges. It is time-consuming to assess and little is known about the way it is influenced by the characteristics of a bridge. In many cases, a bridge needs testing after is has been finished to determine the specifications of a damper. Striving to reduce the environmental impact of bridges, there lies a great potential in using materials with a low environmental impact, such as timber. This research combines the lack of knowledge about dynamic behaviour of footbridges with the need for using timber instead of other materials. It consists of two parts. The first part, the parameter study, investigates the influence of three preliminary design parameters on the dynamic behaviour of a long-span timber footbridge, namely the pylon height, the pylon shape and the amount of cables. The second part, the optimisation study, examines to what extent it is possible to design a long-span timber footbridge that does not need dampers to control excessive vibrations. To this end, a parametric model of a bridge was made in which parameters can be varied and optimised to create realistic design variants. To be able to optimise taking into account dynamic behaviour, a python script was written to automatically determine the type of modes. The results of the parameter study show that the dynamic behaviour can be influenced by the parameters, although the results depend on the specific model, dimensions, parameter values and damping value. The results of the second part show that a with a 14% increase in mass a design variant that does not need dampers to control excessive vibrations can be obtained.