Introduction: The purpose of this study was to develop a self-determination educational package and determine its effectiveness on Self-Directed Learning and Decision making Styles of high school students. Methods: The research method was semi-experimental with pre-test, post-test with the control group and follow up. At first, self-determination educational package was compiled using library studies, then the rate of content validity ratio (CVR) and content validity index (CVI) was determined by the experts. Using a multistage cluster random sampling method, a 22-members class and a 20-members class of 10th grade empirical science filed were assigned to the experimental group and the control group, respectively, that experimental group had 2 students drop. The experimental group received an educational package in eight 90-minute sessions, and the control group did not receive any education. The findings were analysed using covariance analysis and repeated measures analysis of variance. Results: The content validity index (CVI) for all goals in the educational package was 0. 9 to 1, and the content validity ratio (CVR) for all goals in the educational protocol was 0. 8 to 1. Findings showed that the selfdetermination educational package had the most effectiveness in Self-Directed Learning variable, respectively in planning and implementation, learning motivation, Self-Monitoring and then interpersonal communication. Regarding the decision-making Styles, the greatest change was observed respectively in Spontaneous, rational, and then Intuitive decision-making Style of students. Moreover, no meaningful difference between post-test and follow-up was detected, which reveals the stability of learning effects. Conclusions: Self-determination educational package has the potency to promote Self-Directed learning skills, as well as reduce the level of Spontaneous decisions and increase the level of logical decisions of high school students.