The purpose of this study was to investigate the relations between academic rational/irrational beliefs, academic procrastination, and time preferences to study for exams and academic achievement by using the structural equation model. The sample consisted of 281 undergraduate students who filled in questionnaires at the 7-week-long summer course. Students responded to questionnaires assessing their levels of (a) academic procrastination, (b) academic rational/irrational beliefs, and (c) time preferences to study for exams and demographic information sheet. In general, the results showed that rational academic beliefs have a direct impact on academic procrastination and time preferences to study for exams. Academic rational beliefs also have an impact on academic achievement indirectly by mediation of academic procrastination and time preferences to study for exams. The results also showed that academic procrastination has an impact on academic achievement both directly and by mediation of time preferences to study for exams. This study suggested that there is a relation between academic procrastination and rational academic beliefs, which should be addressed further in counseling intervention. Knowledge about the role of irrational academic beliefs and their relations with academic procrastination may assist school/ college counselors to develop interventions for students that suffer from delaying behaviors that negatively affect academic success.