Over the past 20 years, research has consistently affirmed the importance of explicit vocabulary instruction for adult learners of English as a second language (ESL). Given the significant vocabulary demands faced by adult second language readers, ESL teachers must carefully target their instruction for maximum impact and to foster meaningful connections for learners. This practical resource guide for designing and implementing effective vocabulary instruction provides an overview of a three-tiered vocabulary framework, followed by specific recommendations for selecting and teaching vocabulary in the adult second language classroom. Examples of strategies for brief instruction and elaborate instruction are given.