Self-efficacy predicts academic achievement by influencing the effect of skills, previous experience, mental ability, or other self-beliefs on subsequent achievement. Students with high self-efficacy set challenging goals engage in more effective learning strategy use and persevere when encountered by difficult tasks. As a result, students’ academic self-efficacy and its impact on their school achievement should be a focus of educational research. The purpose of this study was then to examine university students’ self-efficacy and its role on their academic achievement. To this end, two Ethiopian well-known government universities were purposefully selected. Of which first year medicine students were again deliberately taken since they are seen facing such problems and experiencing the challenges of handling major courses for the first time. This study thus set out to identify medicine students’ academic self-efficacy viz-a-viz their achievements with particular focus on PC1 students at Jimma and Hawasa Universities. To achieve this objective, data were collected via questionnaire (filled out by 230 PC1 students selected through systematic random sampling) and document review (students’ grade reports), and analyzed using quantitative (frequency, percentage, mean and Pearson’s Correlation) and qualitative techniques. The results indicate that the respondents hold positive self-efficacy in all of the courses except Biochemistry and Embryology. In addition, the study demonstrated that self-efficacy belief predicts academic achievement (high self-efficacy resulted in high academic achievement) except for Environmental Health for which an inverse relationship was observed between the two variables. Based on these findings, it has been recommended that instructors need to enhance students’ academic self-efficacy where it is low and moderate it when it is excessively high.