Empirical studies have shown that Content and Language Integrated Learning (CLIL) seems to be beneficial to receptive vocabulary, which in turn correlates with a higher level of general competence. However, these studies have mainly compared CLIL and Non-CLIL groups matching in age at testing and without a control of other variables such as amount of exposure. The present study, even though exploratory in nature, sets out to fill this gap by comparing groups with the same onset age as well as controlling for other variables. To test general proficiency, the Quick Placement Test (QPT) was used, and the 1,000 and 2,000 frequency bands of the Vocabulary Levels Test (VLT) were delivered to measure functional vocabulary size. CLIL students were found to outstrip their respective Non-CLIL counterparts at the same educational level and to perform as well as an older Non-CLIL sample. Taking together the level of English language lessons and differences in cognitive maturity and amounts of exposure, it is argued that CLIL instruction has intrinsic benefits for receptive vocabulary.