Body dissatisfaction is an important correlate of dysfunctional eating. In the present study (N=208) the primary aim was to test whether women's internal and autonomous motivation can protect against endorsements of societal pressures regarding the ideal female body and against body dissatisfaction. Additionally, the role of others' autonomy support was investigated. Women who reported more Global Self-Determination (GSD) were lower in internalisation of the thin ideal and this association was fully mediated by perceived sociocultural pressure to be thin. Moreover, the positive association between perceived pressure and body dissatisfaction was partially mediated by thin ideal internalisation. Body dissatisfaction was associated with a more controlled regulation of eating, and GSD moderated the association between body dissatisfaction and autonomous regulation of eating. Autonomy support played a role in eating regulation as women with more support reported more autonomous eating. Yet, the support did not moderate the relationship between body dissatisfaction and eating regulation. Future studies should continue to explore the potential facilitative role of autonomy support in promoting a self-determined approach to eating regulation.