Etiological models of eating disorders (EDs) describe body dissatisfaction (BD)as one of the major influences fostering dysfunctional body-related behaviour and disordered eating behaviour. BD is influenced by repeated exposure to thin ideals that evoke high self-ideal discrepancy and result in body-related cognitive distortions such as thought-shape fusion body (TSF-B). The aim of this study was to investigate the covariation of daily media exposure and the experience of TSF-B in a naturalistic setting. It was further analysed whether TSF-B is associated with self-ideal discrepancy, dysfunctional body-related behaviour, and disordered eating behaviour. Moreover, person-related predictors of TSF-B were explored. Altogether, 51healthy female students (mean age 21.06years, SD = 1.76) participated in an ecological momentary assessment study with four daily surveys during 10consecutive days. Exposure with thin ideals in contrast to exposure to unspecific media contents went along with the experience of TSF-B. TSF-B was associated with higher self-ideal discrepancy and dysfunctional body-related behaviour as well as more pronounced disordered eating behaviour, suggesting that TSF-B is a common phenomenon in young healthy females' everyday life. A main effect of trait measures (e.g., pre-existing BD) on TSF-B was observable but has no moderating effect. Thus, a specific vulnerability has not been detected.