The current study was designed to identity if and to what extent differences in motivation exist between high school students, for whom school is mandatory, and undergraduate students in tertiary institutions, who make an active choice to study in an academic institution. This study also explores whether and to what extent motivation affects the achievements of these two groups of learners, and whether motivation is related to their personal, family, and socio-economic background and gender. To examine these questions, 121 participants responded to a 22-item questionnaire on motivation for learning. Findings show that undergraduate students are more highly motivated for learning compared to high school students. Associations were found between learners' personal and academic background and their motivation: Motivation increases with age and as grade average increases. A significant difference was, however, found in motivation levels between learners with average socio-economic status and learners with above-average socio-economic status. No gender effects in learners' motivation were found. Findings of the study shed light on the significant of motivation in high school, which is a significant period in youngsters' lives. High school is a scholastic space that also has the potential to strengthen motivation for learning in the future, in academic studies, as both education systems -- high school and academic education -- affect each other.