The lower rates of COVID-19 vaccination in Western Balkans countries could be partially explained by societal distrust of its citizens, jeopardizing the sustainability of COVID-19 vaccination programs. The aim of the study was to determine the level and predictors of societal trust in five countries of the region. Using an online questionnaire, data were obtained from 1157 respondents from Albania, Bosnia and Herzegovina, Montenegro, North Macedonia, and Serbia. The instrument included a socio-demographic questionnaire, a measure of vaccination behavior, and a scale measuring societal trust. Being a significant determinant of the COVID-19 vaccination behavior in all countries, societal trust considerably varied from country to country (F (24, 4002) = 7.574, p < 0.001). It was highest in North Macedonia (Mean = 3.74, SD = 0.99), and lowest in Albania (Mean = 3.21, SD = 1.03). Younger, female, less religious, and higher educated tended to have more pronounced societal trust in Serbia. In North Macedonia, younger age and lower health literacy predicted societal trust, while in Bosnia and Herzegovina, educational level was the single predictor. In Montenegro and Albania, higher societal trust was significantly predicted by lower health literacy only. The results provide evidence that the determinants of societal trust in Western Balkans vary across countries, indicating the need for different approaches in communication campaigns.