OBJECTIVE:The interplay between parental and child food and physical activity aversion, briefly defined as fear or avoidance of novelty or breaking from routine, may explain such child behaviors as inadequate food consumption and physical activity. Two studies were conducted to investigate the associations between child and parental food and physical activity aversion (child self-reported aversion, parental-reported aversion, and parental perceptions of child aversion) and child food intake and physical activity. METHOD:Parent-child dyads participated in 2 longitudinal studies. Study 1 (food aversion; the baseline [T1] and the 10-month follow-up [T2]) enrolled 924 dyads (1,848 individuals; 54.3% girls, aged 5-11 years old, 88.9% mothers). Study 2 (physical activity aversion; the baseline [T1] and the 7- to 8-month follow-up [T2]) enrolled 879 dyads (1,758 individuals; 52.4% girls, aged 5-11 years old, 83.2% mothers). There was no overlap between the samples enrolled in the two studies. Dyads completed self-report measures; child and parental body weight and height (for calculation of body mass index [BMI] as covariates/potential moderators) were measured objectively. Mediation analyses with 2 sequential mediators were performed. RESULTS:The association between self-reported parental food aversion (T1) and child fruit and vegetable intake (T2) was mediated sequentially by parental perception of child food aversion (T1) and self-reported child food aversion (T2). The same pattern of associations was found for physical activity aversion. Child BMI did not moderate the hypothesized associations. CONCLUSIONS:High levels of parental and child aversion operated sequentially in explaining lower levels of child fruit and vegetable intake and physical activity. (PsycINFO Database Record (c) 2019 APA, all rights reserved).