This chapter reviews corrective feedback studies that focused on the effectiveness of oral corrective feedback on specific morphosyntactic targets in English as a second language. Specifically, this chapter addressed the question of whether the grammatical complexity of the target structure investigated affects the effectiveness of corrective feedback as an instructional intervention. Not only was complexity defined on the basis of formal criteria, but it also incorporated a semantic component from the perspective of the redundancy and transparency of the form–meaning mapping. Eleven studies published between 2006 and 2018 qualified for the research synthesis. The overall findings indicated that, in general, corrective feedback is more effective for simpler grammatical features. The chapter concludes that type of language feature is a relevant dimension to consider in the effectiveness of corrective feedback. The chapter calls for future research on the role of grammatical complexity using categorization methods that consider both formal and semantic complexity features.