Purpose: The purpose of this tutorial is to explain key concepts about vocabulary acquisition and instruction and to translate research from middle school vocabulary interventions into practice recommendations for practitioners. In this tutorial, we consider the relationship between vocabulary and reading comprehension, describe vocabulary acquisition including the development of semantic networks, provide a review of high-quality middle school vocabulary studies, and make recommendations for practice. Method: We reviewed the experimental and quasi-experimental literature examining the impact of vocabulary instruction on the vocabulary and reading comprehension development of middle school students. We searched multiple electronic databases (e.g., PsycInfo, ERIC, Scopus, Google Scholar) using combinations of specific search terms (i.e., "vocabulary," "intervention," "instruction," "middle school," "adolescent"), searched reviews of vocabulary research, and conducted bibliographic searches of included studies. We then extracted information from each included study about the intervention, participants, and outcomes. Results: We identified 17 studies meeting our inclusion criteria. The majority of studies were conducted with students from low socioeconomic status backgrounds. Only 1 study focused exclusively on students with learning disabilities, language impairments, or reading disabilities, highlighting the need for more vocabulary experimental research studies with special populations of students in middle school. Conclusion: After reviewing the middle school studies, we make 5 recommendations based on the literature: (a) teach vocabulary intentionally, (b) teach independent word-learning strategies (morphological analysis), (c) focus on developing semantic networks, (d) increase opportunities to use new words in discussion and writing, and (e) provide a motivating and language-rich learning environment.