This cross-sectional study investigated first (L1) and second (L2) language receptive and expressive vocabulary in a sample of 542 typically developing bilingual children of immigrants (age range 6–13), coming from six different L1 backgrounds in Norway. Results demonstrated that children’s L1 and L2 vocabulary skills increased with age. From a deficit perspective, the study confirms that in each age group, there is a vocabulary gap between the ranges of Norwegian vocabulary known by Norwegian monolinguals and by Norwegian L2 children. At the same time, when an additive, conceptual scoring approach (taking into account bilingual children’s known L1 and/or L2 vocabulary) was used, the persistent gap in vocabulary knowledge diminished or disappeared altogether. This finding is most evident in older age groups. Conceptual scoring provides a more sensitive and positive picture of bilingual children’s overall range of vocabulary. The findings demonstrate a need for more nuanced assessment procedures of semantic knowledge across children’s’ L1 and L2.