This study investigates the evolution of societal values regarding homosexuality and abortion in Croatia, Serbia, and Slovenia from 1995 to 2020. Utilizing data from the World Values Survey, the research examines how these values have shifted in relation to religiosity and institutional changes. The findings reveal significant divergences among the three countries. Croatia and Serbia have experienced an increase in conservative attitudes towards sexuality, particularly influenced by rising religiosity and the impact of religious nationalism. Conversely, Slovenia has shown a liberalizing trend, with decreasing proportions of the population viewing homosexuality and abortion as unjustifiable. The study employs regression models to analyse the influence of religiosity, gender, age, and education on these values. The results indicate that while religiosity is a significant factor, national differences persist even after controlling for it. The paper concludes that historical trajectories and the interplay between formal and informal institutions play crucial roles in shaping values on sexuality. The study highlights the need for further research on the connection between institutional reforms, historical contexts, and value changes.