Across and even within European states, heritage language education (HLE) for pupils with a migration background varies considerably, as do the political and academic discourses surrounding HLE. Due to the intensified public discourse around migration, educational opportunity and multilingualism, research on heritage languages (HL) and HLE has increased in recent years (Mehlhorn, 2020). However, there is still little agreement among scholars concerning the role of HLE for children’s linguistic, educational or personal development. Although studies suggest that support for heritage languages does not bear negative consequences, empirical findings on the optimal design and delivery of heritage language lessons (HLLs) are still lacking. How, then, should research be prioritised in different contexts? We consulted a large cross-national survey on research priorities for multilingualism and language education (Duarte et al., 2020) in order to uncover findings relating specifically to HLE. The findings derive from the rankings of research priorities by panels of expert participants (n = 300) in five European countries: Germany, Italy, the Netherlands, Portugal and Spain. The rankings indicate that research on HLE is considered important in all countries, albeit to a lesser degree in Spain. Research on the effects of HLE on the majority language and subject comprehension was deemed most important by the expert participants, or at least as urgent as effects on the heritage language itself. Experts also attributed importance to topics concerning HLE quality. Other findings point to country-specific priorities. We present the overall results from two sets of questions concerning research on HLE and attempt to offer qualitative interpretations of these findings.