In second language (L2) vocabulary research, much attention has been paid to how learners can be supported to acquire vocabulary and how teachers can be better prepared to teach vocabulary in the language classroom. As research efforts have been devoted largely to exploring effective vocabulary teaching strategies and techniques, it remains unclear what teachers know and believe regarding L2 vocabulary acquisition beyond the commonplace conception that teaching and learning are interrelated. The present study explored the epistemological and pedagogical beliefs about vocabulary development reported by four in-service English language teachers in Hong Kong through in-depth semi-structured interviews. It also examined the major factors shaping those beliefs. The results suggest that although the interviewees considered vocabulary teaching to be pivotal, they seemed to focus only on certain aspects of lexical knowledge and rely on a limited range of strategies in teaching vocabulary. Implications for L2 education and teacher development are drawn.