Content-based instruction is a favoured methodology for approaching L2 language instruction. Although vocabulary development is one language area where advanced learners could grow, there is little research focusing on vocabulary instruction in content-based Spanish L2 courses at US universities. This study analyses a corpus of 25 hours of instruction comprising two upper-level culture courses and one upper-level linguistics course taught by three experienced instructors. Although the courses differed in content and the instructors' pedagogical practices, all three offered opportunities for learners to increase vocabulary breadth and depth through lexical elaborations. Interactive lectures, review of content, and text-based discussions contributed to a higher number of elaborations. Moreover, students' participation was fundamental to increasing the interactive nature of those elaborations. Findings show that specialised and general vocabulary as well as proper nouns and even new terms in English were targeted for elaboration. Overall, this study presents a positive view of the content-based classroom as a place for vocabulary development. The study further suggests that an even richer instructional context could be created by helping teachers become more aware of the need to plan for and implement classroom opportunities for increasing vocabulary knowledge.