While research on how classroom climate impacts students’ bullying behavior has increased over past decades, studies on how a well-functioning class climate may impact the classroom prevalence of victims of bullying are scarce. Class climate refers to the quality of collective interpersonal relationships among students in a school class. Thus, in line with group socialization theory and the social climate framework, the present study aimed to examine, at the class level, possible short-term longitudinal links between varying degrees of well-functioning class climate and the class proportion of victims of bullying. Class proportion here refers to the percentage of students in the class who are bullied. The study was based on responses from a short-term longitudinal population of almost 5000 students, fourth to ninth graders in a Swedish municipality, who completed a questionnaire in fall 2022 (Time 1, N = 4,964), and spring 2023 (Time 2, N = 4,799). Because the survey was administered anonymously, it was not possible to longitudinally follow students at the individual level. However, the dataset made it possible to longitudinally follow each school class. A class-level path model was therefore estimated to investigate whether a well-functioning class climate and class proportion of victims at Time 1 predict well-functioning class climate and class proportion of victims at Time 2. The main findings emphasize how school classes with a well-functioning class climate were more likely to have a lower proportion of victims over time. In addition, a well-functioning class climate at Time 1 positively predicted a well-functioning class climate at Time 2, and the proportion of victims in school classes at Time 1 positively predicted the proportion of victims in school classes at Time 2. These results highlight the critical role of fostering a positive class climate in reducing bullying victimization at the class level.