Internationally, there is an under-supply of intellectual capital to provide for STEM-related employment. One contributing factor is the low number of female students selecting STEM school subjects and careers. Despite the literature recommending students engage in STEM activities earlier, many initiatives are not implemented until high school. This paper reports on an Australian project named MindSET-do which provided students with early positive STEM experiences prior to high school to raise awareness of, interest in, and aspirations for STEM-related subjects and careers. The case study surveyed n = 107 Year 6 boys' and girls' interests, ability beliefs and expectations in STEM school subjects and careers. Students' awareness and interest in STEM-related subjects and careers increased significantly following experiences with inquiry-based STEM activities, X[superscript 2](1, n = 107) = 4.57 to 63.67, p < 0.05. Expectancy for success in mathematics was significantly higher for males than for females (U = 1125, p = 0.044, r = 0.2). Expectancy for success in science was slightly lower for the female group, but p > 0.05. Logistic regression found females were 24 percent less likely to have a positive view of mathematics than males (p = 0.003). Gender differences in STEM ability versus ability beliefs and expectancies for success are discussed, with recommendations for earlier positive experiences with STEM tasks.