This article presents a model of loneliness that incorporates characteristics of the social network, background variables, personality characteristics, and evaluative aspects. The most salient aspect of this approach is its emphasis on cognitive processes that mediate between characteristics of the social network and the experience of loneliness. A total of 554 adult men and women served as respondents. The program LISREL, a causal modelling approach, was used to analyze the data. The LISREL program includes a goodness-of-fit test that indicates the degree of fit between a particular model and the data. The hypothesized model made a valuable contribution to the understanding of loneliness: It accounted for 52.3% of the variance in the data set. One of the model's major advantages is its ability to disentangle both the direct and the indirect causal influences of the various factors on loneliness.