Anxiety disorders are the most prevalent mental disorders in developed countries. Obesity is hypothesized to be a risk factor for anxiety disorders but evidence supporting an association between these two conditions is not clear. The objectives of this paper were to systematically review the literature for a link between obesity and anxiety disorders in the general population, and to present a pooled estimate of association. We performed a systematic search for epidemiological articles reporting on obesity (explanatory variable) and anxiety disorders (outcome variable) in seven bibliographical databases. Two independent reviewers abstracted the data and assessed study quality. We found 16 studies (2 prospective and 14 cross-sectional) that met the selection criteria. Measures of effect from prospective data were mixed but cross-sectional evidence suggested a positive association between obesity and anxiety. The pooled odds ratio from cross-sectional studies was 1.4 (confidence interval: 1.2-1.6). Subgroup analyses revealed a positive association in men and women. Overall, a moderate level of evidence exists for a positive association between obesity and anxiety disorders. Questions remain regarding the role of obesity severity and subtypes of anxiety disorders. The causal relationship from obesity to anxiety disorders could not be inferred from current data; future etiologic studies are recommended.