Background and Objectives: The uptake of COVID-19 vaccines in Western Balkan countries is lagging far behind the European Union average, with vaccine hesitancy as a serious threat and reason for the insufficient vaccination coverage and suboptimal herd immunity. Understanding factors that influence vaccine uptake in those countries is critical for development of effective vaccination promotion strategies for Western Balkans. Methods: Cross-sectional research was carried out from July to October 2021. Convenience sampling included 1605 individuals aged 18 and above from Albania, Bosnia and Herzegovina, North Macedonia, Montenegro and Serbia. Online questionnaire was shared through social media. Results: In all countries both vaccinated and unvaccinated respondents consider the vaccine against COVID-19 to be more safe than effective. The most positive attitudes towards COVID-19 vaccine safety are found in North Macedonia (M=3.61, SD=1.17) and Serbia (M=3.50, SD=1.26). Around 40% of respondents believe that pharmaceutical companies are reluctant to publish research reports on risks of adverse reactions to vaccines. Over 70% respondents in Albania and North Macedonia and 66,5% in Montenegro and Bosnia see important role for primary health physicians in educating people on importance of vaccination and consider them as trusted sources of information about COVID-19. Women and those with higher education (Bosnia and Herzegovina, Montenegro and Serbia) manifest a more pronounced personal sense of social responsibility in achieving collective immunity. Respondents who assessed themselves as more religious consider vaccine against COVID-19 as less safe and effective, demonstrate less trust towards societal factors and are less likely to demonstrate social responsibility in the context of vaccine behaviour. Conclusions: Family physicians should have a key role in promoting vaccination and educating public in Western Balkans. Partnerships with representatives of religious groups and awareness campaigns with focus on young people should be the core of public health interventions addressing vaccine hesitancy in Western Balkans.