For academic writers to use a word, they must know not only its basic meaning, its pronunciation, and the contexts in which the word is used, they must also possess more complex knowledge—a word’s collocational patterns and grammatical constraints (Colombi & Schleppegrell, 2002; Halliday, 1987, 1994). Gaining the lexicogrammatical knowledge needed to use words appropriately in college writing is a particular challenge for Generation 1.5 ESL writers. These students, who come to college with a rich academic and nonacademic vocabulary developed through years of formal study and daily interaction in English, often produce awkward or even ungrammatical sentences when they use this vocabulary productively. This paper focuses on lexicogrammatical errors commonly found in the academic writing of Generation 1.5 ESL students and discusses how discourse-based strategies for teaching grammar can be adapted to help these learners use academic vocabulary in a semantically and grammatically appropriate way. These strategies include having students look at models, teaching dictionary use, and developing students’ analytical self-editing strategies.