This study explored the influence of experimental goal setting and planning on the attitudes toward science, self-efficacy, inquiry performance, and achievement of students with low academic performance. A total of 71 students aged 16-18 were randomly divided into a treatment group (with goal setting and planning) and a control group (without goal setting and planning). A microcomputer-based laboratory focused on Boyle's Law, coupled with an inquiry worksheet, was assigned. Based on Winne and Hadwin's model of self-regulated learning, scaffolding was offered to the treatment group to promote goal setting and planning. Data were collected from the worksheet, the Attitudes toward Science Scale, the Self-efficacy of Scientific Inquiry scale, and the Boyle's Law Conceptual Test. The results showed that both the treatment and control groups improved significantly from the pre- to post-conceptual tests. In the treatment group, the male students gained significantly more conceptual knowledge than the female students. Regarding attitudes toward science, the male students' scores on the post-test were higher than those of the females. It is concluded that the male students were more positive regarding goal setting and planning in the inquiry activity, whereas the female students did not benefit as much.