This very low natural frequencies of compliant offshore structures have raised the concern about the significance of the dynamic action of wind in the response of such platforms. In this thesis the effect of wind loads on the response of a Tension Leg Platform is examined in detail.;The study examines the importance of wind loads through the use of two different numerical models and through an experimental study carried out in a wind-wave flume, where a dynamic model of a Tension Leg Platform was subjected to the action of properly scaled random wind and wave loads. The numerical models include a full diffraction analysis and the effect of second-order, non-linear wave drift forces. The study is the first, where a physical model of a Tension Leg Platform has been tested in a wind-wave facility, and is believed to be the first numerical study where the modeling of wind forces is accompanied by a complete model of the wave forces.;The agreement between the results obtained from the numerical simulations and the experiments was good, indicating that the numerical models used in this thesis can adequately predict the response of a Tension Leg Platform to the combined action of wind and wave loads.;The effect of the wind on the surge response of the platform was found to be strongly dependent on the length of the fetch of water over which the wind had been blowing and the duration of the wind storm. In cases where the fetch is short or the storm duration is short, so that large waves cannot develop, it was found that the wind dominated the surge response behaviour of the platform. In the cases where large waves were allowed to develop, the response was not governed by the action of the wind, but the dynamic action of the wind did contribute to the total surge response. In general, the wind induced surge response and the second-order wave induced surge response were found to be of similar importance.;The yaw response of the platform was found to be dominated by the action of wind