In 1923, the first referendum of the Republic of Estonia took place. It was held on the question of religious studies. The referendum was a reaction to the policies of the left and left-leaning political parties that together held a majority in the Constitutional Assembly (1919–1920) and the first parliament (1921–1923), and thus were able to construct the new school system. Since all the leftist political parties were avowedly secular, they excluded religious studies from all public schools – even as a voluntary subject. A public initiative launched primarily by the dominant Lutheran Church that would have allowed religious studies to be taught as a voluntary subject in public primary schools was put to the voters in 1923. 71.2% of the votes were cast in favour of the proposal.

This article uses the official municipal-level results of the referendum to study the role of eight factors related to turnout, politics, socio-economic and cultural composition in influencing the results of the referendum. A key question is whether we can interpret voting against religious studies as a sign of secularisation.

The article shows that the vote share in favour of religious studies was higher in municipalities with higher turnout compared to the parliamentary elections held three months later. This means that the religious forces were better at mobilising their supporters than the secular forces. Regarding political factors, the vote share of leftist parties was clearly linked to a higher share of votes cast in opposition to the proposal. The municipalities that experienced communist rule and the anti-religious policies enacted by the communists during the Estonian War of Independence show lower shares of opposition, but this may be related to their ethno-religious composition. It seems that members of minority churches, however, were against the reinstitution of religious studies since they feared the domination of the Lutheran Church. This observation only relates to ethnic Estonians and not ethnic Russians. The anti-religious forces also claimed that reintroducing religious studies would mean higher taxes. This argument had no effect in the countryside, but its effect can be seen in urban areas.

Asymmetrical mobilisation and voting against religious studies for religious and economic reasons presents difficulty in unequivocally interpreting the vote share against religious studies as a sign of secularisation. Still, these factors can mostly be checked for in a multivariate study design.