Vocabulary knowledge is an important predictor of literacy and broader academic outcomes, and children's literature is a rich source of sophisticated vocabulary. This study investigated the effect of providing instruction in word meanings as an adjunct to story-book read-aloud sessions in Grade One classrooms. The main intervention programme ran for 18 weeks over three terms in low socio-economic status (SES) schools. Two intervention models incorporating explicit instruction components were compared with existing classroom practice. Teaching a greater number of word meanings more briefly was contrasted with teaching fewer words in greater depth. Pre- and post-instruction vocabulary knowledge was assessed using curriculum-based assessments. Both explicit approaches were more effective in improving word learning than a traditional constructivist approach. Increased intensity of instruction resulted in better learning for individual words. There was no discernible carryover to scores on standardised vocabulary tests.