The Jesuit missions in South America were an important factor in the evangelisation of the continent during the seventeenth and eighteenth centuries. However, although the history and cultural aspects of the distinctive settlements that the missionaries created for indigenous peoples have been examined extensively, studies that address issues relating to archaeoastronomy have only recently begun to appear, primarily in relation to the orientation of churches built for Guaraní peoples in the Jesuit Province of Paraquaria (Province of Paraguay). The current paper continues and complements these studies of the region with the first archaeoastronomical study of the nearby Jesuit missions of Chiquitos in eastern Bolivia, focusing on measurements taken at the ten mission churches, interpreted within the context of the surrounding landscape and the characteristics of the villages where the churches are located. Our results show that in contrast to the churches of the Province of Paraquaria, where north–south meridian orientations predominate, half of the studied Chiquitan Jesuit churches show potential canonical orientations that seem to be aligned to solar phenomena, with three exhibiting precise equinoctial orientation. In this paper I propose reasons for these orientations, including the possible relevance of illumination effects on significant internal elements within the churches – effects that were generally sought in Baroque church architecture.