ALT Many parents express concerns for their children’s multilingual development, yet little is known about the nature & strength of these concerns – especially among parents in multilingual societies. This study addresses this gap by examining the concerns of 821 Quebec-based parents raising infants & toddlers aged 0–4 yrs w multiple langs in the home. Factor analysis of parents’ Likert-scale responses revealed that parents had 1. concerns re: the effect of children’s multilingualism on their cognition & 2. concerns re: children’s exposure to & attainment of fluency in their langs. Concern strength was moderate to weak; cognition concerns were weaker than exposure-fluency concerns. Transmission of a heritage lang, transmission of 3/more langs, presence of developmental issues & less positive attitudes towards childhood multilingualism were associated w stronger concerns. These findings have both theoretical & practical implications.