This classroom study investigated the effects of oral teacher and peer corrective feedback on the acquisition of the German present perfect tense, including auxiliary verb selection (a rule-based structure) and past participle formation (an item-based structure). Intermediate learners of German were assigned to a teacher feedback condition, a peer feedback condition, or a control group. Learners in the teacher feedback group were corrected by their course instructor, while learners in the peer feedback group were trained to provide guidance to each other at the beginning of a two-day instructional treatment. Results from both an immediate and delayed posttest showed that while both experimental groups significantly improved in grammatical accuracy with both auxiliary selection and the past participle, the largest improvement was seen among the learners in the peer feedback group. These findings suggest that peer corrective feedback heightens learners' awareness of linguistic forms and that learners who provide such feedback may benefit not only from receiving but also from providing it. The results further demonstrate that peer feedback can be effective with less-proficient learners and with different types of grammatical structures.