Background. Precursors driving leisure-time sedentary behaviors remain poorly investigated, despite their detrimental consequences. This study aimed to investigate the predictive validity of controlled and automatic motivational precursors toward reducing sedentary behaviors and being physically active on leisure-time sedentary behaviors. The influence of demographic, physical, socio-professional, interpersonal, and environmental variables on leisure-time sedentary behaviors was also examined and compared with the associations of motivational precursors.Methods. 125 adults completed questionnaires measuring controlled motivational precursors (i.e., attitudes, intentions, perceived competence), demographical (i.e., sex and age), physical (i.e., body mass index), and interpersonal (i.e., number of children) variables. Regarding automatic motivational precursors, habit strength and approach-avoidance tendencies were captured using the Self-Report Behavioral Automaticity Index and a manikin task. Leisure time, time and physical activity at work were computed as socio-professional variables, days of the week and weather conditions were recorded as environmental precursors. Participants wore an accelerometer for seven days and leisure time was identified thanks to notebooks. Associations between the different precursors and the leisure-time sedentary behaviors were examined in linear mixed effect models.Results. Intention to be physically active (b = -1.089, p = .028) and habit strength toward physical activity (b = -0.943, p = .019) were negatively associated with leisure-time sedentary behaviors. However, motivational precursors toward reducing sedentary behaviors were not associated with the dependent variable (ps. > .098). Demographical (b = 5.043, p = .002 for sex and b = 0.493, p = .011 for body mass index), socio-professional (b = -1.318, p =.040 for leisure time and b= 1.861, p = .005 for time at work), interpersonal (b = -2.037, p = .002 for the number of children), and environmental (i.e., p = .028 for the global effect of the day of the week and p < .001 for the global effect of the weather conditions) precursors were more strongly associated with leisure-time sedentary behaviors.Conclusion. Our findings show that, in comparison with demographical, socio-professional, interpersonal and environmental variables, the influence of motivational precursors on leisure-time sedentary behaviors is limited. This study lends support for the adoption of a broad-spectrum of precursors when predicting sedentary behaviors.