Aims of this study were to examine gender differences between male and female students when it comes to their past performance in physics, subjective task value, their self-efficacy and academic procrastination and to examine whether self-efficacy and subjective value play a mediator role in the relationship between the students` past performance in physics and the academic procrastination of learning physics. The participants were 285 high school students (grades 2 and 3) in Zagreb. As a theoretical framework for the research Eccles and colleagues’ (1983) expectancy-value model was used. The instruments used in the study measured students' self-efficacy beliefs, four components of subjective task value (attainment value, intrinsic value, utility value and costs) and academic procrastination. The results indicate that male and female students procrastinate equally and do not differ significantly in their past performance in physics. Furthermore, task values (attainment value, intrinsic value, utility value) of physics are significantly lower for female students than for male students. Additionally, female students have lower self-efficacy in physics and their perceived cost is significantly higher. Past performance, subjective task value, and self-efficacy were in negative correlation with academic procrastination, while their perceived cost is in positive correlation. The results of the mediation analysis indicate that the perceived cost, as an independent component of subjective task value, has a mediating role in the relationship between past performance and academic procrastination, whereas self-efficacy and other components of subjective task value do not show such a relation.