This classroom study investigated the effectiveness of form-focused instruction and peer feedback training to improve grammatical accuracy and thereby maximize learning opportunities during peer interaction. Eighty-seven third-semester learners of German were assigned to a PI group (peer interaction only), an FFI group (peer interaction and form-focused instruction), or a PFT group (peer interaction, form-focused instruction, and peer feedback training). During an instructional intervention over 3 class periods, participants in all 3 groups engaged in the same peer interaction activities, but only the FFI group and the PFT group received form-focused instruction on the grammatical target structure, the German present perfect tense. Critically, only the PFT group was trained to provide corrective feedback to peers. Results from a pretest and two posttests, all of which included an oral production task and an error correction task, showed that peer interaction was effective when combined with form-focused instruction, but more effective when peer feedback training was also provided to learners. These results underscore the importance of instruction on peer feedback for more successful peer interaction activities.