This study examined a group of primary Swedish students' conceptions of their own motivation for learning. Altogether, 68 students in Grades 3, 6, and 8 participated in the study, in which similarities and differences among students in the three grades were considered. Theoretical and methodological aspects were guided by the phenomenographical approach. For most students, positive and negative influences on motivation emerged in seven distinct categories: feelings, teachers, teaching, subjects, learning environment, classmates, and well-being. The apparent importance of good teachers, structured and varied lessons, practical aesthetic subjects and more group-rooms was similar across the three different grades. Differences that emerged were students' reduced joy in learning, decreased interest in mathematics, higher levels of stress and pressure, more worry and anxiety, higher degree of preparation for the future, and a greater need for individualisation for the older students. The study's results confirm previous research but also provide new knowledge about variations across the grades and more specific factors that promote or inhibit students' motivation to study.