This paper starts with the fact that noise annoyance is partly due to acoustic factors, partly due to so-called moderating variables, i.e. personal and social aspects of the residents. Noise annoyance is considered to be the (long-term) negative evaluation of living conditions with respect to noise. This evaluation is not simply dependent on past disturbances, but on attitudes and expectations, too. The personal factors influencing the evaluation and described here are: Sensitivity to noise, fear of harm connected with the source, personal evaluation of the source, and coping capacity with respect to noise. The social factors described here are: General (social) evaluation of the source, trust or misfeasance with source authorities, history of noise exposure, and expectations of residents. For most of these variables, data from different community studies are used in order to illustrate the respective moderating effect on annoyance. In addition, some of the moderators are presented as possible tools in order to reduce noise annoyance. It is expected that a significant decrease in a negatively moderating variable is as effective in reducing noise annoyance, as is a significant decrease in noise level.