The concept of hands-on, heads-on, and hearts-on (3Hs) education, which conceptualises "whole-child" development in terms of a child's cognitive, social, physical, and affective domain can be appropriately integrated into elementary engineering education. This study aimed to assess parents' perceptions on a 3Hs elementary engineering education program, "Let's Go to Mummie's Lab", which they participated as co-facilitators. Using survey questionnaires and interviews, the parents' opinions on this 3Hs program were collected and analysed. The study found that the parents gave positive responses to this 3Hs program from the aspects of training session, teaching materials as well as the benefits of this program to the parents themselves and the young students. The parents suggested that making the activities more diverse and prolonging the duration of this program could ensure its sustainability. Training session for parents and physical environment also needed to be improved. This study suggests that 3Hs elementary engineering education can be promoted through activity-based, constructivist education environment, interest-based learning, and play. This research encourages schools to involve parents in promoting 3Hs elementary engineering education for the benefits of stakeholders, including parents and young children.