This study examines the influence of design-based learning on 25 eighth-grade students' design-thinking mindsets, that is, on the mental outlook that they adopt habitually when they engage in design thinking. It also compares changes in design-thinking mindsets across individuals of different genders and different levels of experience in design. We collected data by using a self-reported Likert-scale questionnaire. We used Wilcoxon signed-rank tests to compare the students' design-thinking mindsets before and after design-based learning. We utilized Mann-Whitney U tests to identify differences between male and female students and between students with different levels of prior experience. The results indicate that the influence of design-based learning on design-thinking mindsets depends on gender and prior experience. Careful scaffolding is necessary to enable all students to develop their design-thinking mindsets when they collaborate in design-based learning.