The twentieth-century history of second language (L2) education has been characterized by a search for more effective ways of L2 education. The search has led to various approaches, and perceptions of and attitudes toward the role and effectiveness of instruction in L2 education has been affected by these approaches. The role and effectiveness of instruction has important pedagogical implications. This study attempts to review, analyze, and synthesize previous studies on the role and effectiveness of L2 grammar instruction. The study starts by presenting a brief overview of major issues in L2 instruction research. It then looks into studies that investigate the effects of various instructional types and finds that their findings and conclusions are conflicting, leaving an impression that the effectiveness of grammar instruction is inconclusive at best. The study ends with a discussion of “problems” that the reviewed studies reveal.