Grammar teaching has traditionally consisted of giving learners opportunities to produce specific grammatical structures. Such an approach may prove ineffective because it does not take account of how learners acquire grammatical structures (e.g., Krashen, 1982). This article examines an alternative approach to grammar teaching— one based on interpreting input. This approach emphasizes helping learners to notice grammatical features in the input, comprehend their meanings, and compare the forms present in the input with those occurring in learner output. The rationale for the approach is discussed as are the principles for designing interpretation tasks for grammar teaching.