This thesis examines attitudes related to non-vaccination against COVID-19 from a moral psychological perspective. Specifically, the aim was to examine moral polarization on the issue of vaccination, namely which attitudes that people, who are vaccinated against COVID-19, have toward people, who are not vaccinated, and how these attitudes are related to morality. First, the overall research aim, the cultural psychological approach, and key terms were outlined, after which a theoretical framework was constructed based on theories related to moral psychology. Specifically, Moral Foundations Theory, the theory of upward social comparison (moral reproach), and moral framing theory provided a theoretical basis for understanding polarization and vaccination from a moral psychological perspective. This theoretical framework laid the foundation for the construction of a moral pluralist framing study, intended to examine the attitudes of vaccinated toward unvaccinated, and if these attitudes are related to different moral framings and values, and how this relates to political ideology. Data was collected online, by recruiting respondents for a questionnaire, involving both ratings and open-ended questions (N=109). Afterwards, the data was analyzed both quantitatively to identify general tendencies in the data, and qualitative with Qualitative Content Analysis to gain an in-depth perspective on the moral dimensions of the attitudes exhibited in the text-answers. The most consistent findings were that, in line with the theory, the moral foundation of harm/care was the most understandable moral foundation, while purity was the least understandable. Additionally, it was consistently found that respondents, who identified as moderate or far right, were more understanding of non-vaccination than were people who identified as any other political leaning. In the qualitative analysis, it was found that the primary reasons for being supportive of vaccination were related to showing care for others/preventing harm, and displaying trust in authorities. It was also found that negative attitudes toward unvaccinated were prevalent, particularly among the moderate and far left, supporting the interpretation that non-vaccination is a morally polarizing social issue. The main reason for being understandable of non-vaccination was related to the moral foundation of liberty, particularly considering vaccination to be a matter of personal choice, but also individual concerns related to the vaccine were present. Meanwhile, reasons related to skepsis regarding the vaccine and the authorities’ handling of the pandemic was limited. After the data analysis, reflections related to the methodology of the study were outlined, along with considerations of limitations that should be considered when interpreting the results of the study. The findings and their implications were related to and interpreted through the theoretical framework and compared to relevant existing literature, with which the results were generally consistent. These implications were used to construct theoretically and empirically grounded suggestions for counteracting polarization in relation to non-vaccination, but also polarization in society in general. Additionally, relevant areas for future research were suggested. Above all, it is suggested that promoting understanding of the values that motivate others can increase empathy and tolerance of other people and thereby reduce moral polarization.