Sustaining careers and motherhood are particularly challenging in highly masculinized science, engineering, and technology (SET) sectors. We explore this issue using a social comparison theory perspective, drawing on interviews with professional engineers and scientists from four companies, located in Italy, France, and the Netherlands. We examine how decisions to reduce working hours are influenced by perceived ideological, normative, and policy contexts. Despite contextual differences in opportunities and perceived entitlements and supports for family-friendly working hours, we found that sense of entitlement to do so without forfeiting career progression is limited across all the contexts. This attests to the enduring power of gendered organizational assumptions about ideal SET careers. Nevertheless we present examples of three women who achieved senior roles despite working reduced hours and discuss combinations of conditions which may facilitate sustainable careers and caring roles.