Background: There is a well-known gender disparity in the engineering field. Three of the most important factors related to the participation of women in engineering are differences in perceived societal relevance, technical self-efficacy, and tinkering self-efficacy. Purpose/Hypothesis: Soft robotics is a relatively new engineering application with the potential to address these three factors. We investigated whether participation in a soft robotics design experience would improve students'--especially girls'--perceptions of engineering in contrast to a traditional, rigid robotics experience. Design/Method: Soft robotics curriculum materials were developed for high-school engineering classes using design-based research. Seven teachers delivered soft and rigid robotics lessons; then 293 students reported their perceptions of motivation, interest, and self-efficacy following the lessons and retrospectively. We examined the relationship between gender and lesson type and differences in perceptions of engineering over time. Results: The soft and rigid robotics experiences promoted engineering interest and general, experimental, tinkering, and design self-efficacy. Girls' perceptions of tinkering self-efficacy particularly benefitted from the soft robotics lesson, mitigating gender differences. A robustness check compared the outcomes of different statistical models and verified the stability of the findings. Conclusions: Soft robot design experiences emphasize materiality and iterative design, which contribute to enhanced tinkering self-efficacy. The use of soft robotics in education represents a promising opportunity to integrate authentic engineering experiences, broaden perceptions of engineering, and support the development of future engineers.