This study examined the unique contribution of Home Literacy Environment (HLE), Classroom Literacy Environment (CLE), and parent and teacher expectations to the development of Dutch (L1) and English (L2) vocabulary in children in Dutch-English bilingual primary education. The children (n = 106) were tested on vocabulary in both languages in kindergarten (m[subscript age] = 5-10) and grade 1 (m[subscript age] = 6-10). Their parents (n = 106) and teachers (n = 16) filled out questionnaires on respectively HLE and CLE, and shared their expectations of children's future L1 and L2 achievement through a second questionnaire. Results indicated that L2 HLE correlated with L2 vocabulary and number of L1 books at home correlated with L1 vocabulary. L1 vocabulary development was predicted by teacher expectations, but not by parent expectations, HLE or CLE. L2 vocabulary development was predicted by parent expectations, but not by teacher expectations, L1 vocabulary level in kindergarten, HLE or CLE. These findings highlight the importance of parent and teacher expectations in early bilingual vocabulary development. They suggest a unique but also combined role of two systems in which children learn and develop a second language: the home and the classroom.