Introduction. Women's sexual function may be influenced by various factors including medical conditions, trauma or abuse, medications, relationship dynamics, relaxation, mood, and body image. However, few studies have explored the influence of a woman's genital self-image on her sexual function or behaviors. Aims. The purpose of this study was to establish a reliable and valid measure of female genital self-image, the Female Genital Self-Image Scale (FGSIS), and to assess the relationship between scores on the FGSIS and women's sexual function. Methods. The FGSIS was developed in two stages. Phase One involved an analysis of cross-sectional paper-based survey data and a review of the literature. Phase Two involved a cross-sectional internet-based administration of the scale items to a total of 1,937 women. Main Outcome Measures. Psychometric properties of the scale were evaluated through the use of reliability analysis, factor analysis, and score differences based on women's experience of orgasm from receiving cunnilingus or from self-masturbation with a vibrator. Correlation analysis was used to explore the relationship between female genital self-image and scores on the Female Sexual Function Index (FSFI). Results. The scale was found to have sufficient reliability (Cronbach's alpha = 0.88) and one factor that explained 59.23% of the variance. Women who had ever experienced orgasm as a result of cunnilingus or self-masturbation with a vibrator and women who reported having had a gynecological exam in the previous 12 months had significantly higher FGSIS scores than those who had not (P < 0.001). Scores on the FGSIS were positively and significantly correlated with scores on all FSFI domains (P < 0.001), including the Total score, with the exception of the Desire domain. Conclusion. The FGSIS was initially found to be a reliable and valid measure though further research is needed to understand its properties in diverse populations. In addition, female genital self-image was found to be positively related to women's sexual function. Herbenick D, and Reece M. Development and validation of the female genital self image scale. J Sex Med 2010;7:1822-1830.