The production of wind energy is becoming increasingly important worldwide, with the result that greater numbers of the population are being exposed to wind turbine noise. There is evidence that wind turbine noise has a high annoyance potential, which might be caused by specific sound characteristics such as amplitude modulation. Compared to road traffic noise, however, knowledge of the annoyance effects of wind turbine noise remains scarce. In this study, the annoyance of wind turbine noise and road traffic noise were investigated and compared. To that aim, listening tests were done in the laboratory, allowing controlled experimental conditions and the exclusion of potential effect modifiers such as the visual appearance of wind turbines in field surveys. For the listening tests, specific sound scenarios were generated, either by sound synthesis (wind turbine noise) or by mixing of single pass-by recordings (road traffic noise). The set of sound scenarios enabled auralisation of variations of three variables potentially influencing annoyance, namely source type (wind turbine, road traffic), sound pressure level, and temporal level variation (without, periodic, or random variation). Subjects were exposed to these different sound scenarios, and their ratings on subjectively perceived annoyance were collected. The factorial design of the experiment allows separating the individual contributions of the above three variables to the annoyance ratings. Here, the setup of the listening tests, the most important results and possible applications in environmental impact assessment are presented.