The aim of the current study was to explore whether developmental trajectories of body satisfaction from adolescence to young adulthood predicted measures of sexual satisfaction in young adulthood, even when controlling for important covariates such as gender, weight development, relationship status, mental health, and frequency of sexual intercourse and masturbation. Data were collected from a population-based prospective cohort of Norwegian adolescents (n = 2,587) over a period of 13 years in four waves (1992, 1994, 1999, and 2005; mean age = 14.9 in 1992, 57.3% women). Latent growth curves were estimated for body satisfaction and Body Mass Index (BMI). Men reported higher sexual satisfaction, sexual activity, baseline body satisfaction, and BMI than women. The developmental trajectories revealed a slight increase in body satisfaction and BMI from adolescence to young adulthood in both genders. Moreover, structural equation models showed that baseline body satisfaction in both genders predicted sexual satisfaction as a young adult, independent of relationship status and frequency of sexual activity. Neither the development of BMI nor of body satisfaction predicted sexual satisfaction. The results elucidate the vital role of body satisfaction in sexual satisfaction in adults and the importance of addressing body dissatisfaction in childhood. Despite a well-documented cross-sectional association between body satisfaction and sexual satisfaction (Byers & Rehman, 2014; Woertman & van den Brink, 2012), knowledge about developmental processes explaining variations in sexual satisfaction is lacking. The body is a salient visual stimulus in social interactions, and our appearance is a source for both self-evaluation and communication from an early age (Cash, 2011). The current study contributes to the literature by providing information about how body satisfaction prospectively predicts sexual satisfaction for both women and men. The role of factors that may be confounders of the body satisfaction-sexual satisfaction association are also examined. For this purpose, data from a large, representative 13-year longitudinal study encompassing adolescence and young adulthood were used. The Relationship Between Sexual Satisfaction and Body Image Sexual satisfaction is "an affective response arising from one's subjective evaluation of the positive and negative dimensions associated with one's sexual relationships" (Lawrance