Online sexually explicit material (SEM) is a popular media source, but little is known about its association with body image. This study explored whether perceived realism of SEM mediated the direct association of SEM use on body image while accounting for gender differences. Young adults (N = 393; ages 19 to 30; 53.4% women) recruited through a crowdsourcing Web site completed an anonymous online survey that assessed SEM use, perceptions of the realism of SEM, and body image. Body satisfaction, genital self-image, comfort being nude, penis-/breast-size satisfaction, and self-esteem were used to create the variable of body image. SEM use had a positive indirect association with body image through perceived realism for both men and women. Follow-up analyses revealed this association was due to body satisfaction and self-esteem in men and comfort being nude and self-esteem in women. Findings are discussed in terms of implications for clinical applications and understanding young adults' body image.