Cognitive and behavioural models of body dysmorphic disorder posit that selective self-focused attention via mirror gazing plays a key role in the aetiology and maintenance of the disorder. However, there is little empirical support for these theoretical claims. This study aimed to induce self-focused attention via mirror gazing to examine the proposed theoretical effects on body image, distress, body-focused shame, and self-esteem. Fifty-one non-clinical participants (78.43% female) were randomly allocated to one of the two conditions: low self-focused attention (i.e., looking into a mirror placed 100 cm/ 39 in away) vs. high self-focused attention (i.e., focusing on a disliked part in a mirror placed 10 cm/ 4 in away). Following 5 min of mirror gazing, the high self-focused attention condition experienced decreased satisfaction with appearance, perceived attractiveness, and self-esteem, and increased distress about appearance, distress about disliked parts, urges to change appearance, and body-focused shame. Approaching the mirror from a distance appeared to have no effect. Findings are consistent with theories suggesting that self-focused attention and mirror behaviours might contribute to the development of body dysmorphic disorder and maintain its psychological effects.