This study compared the academic achievement and teacher-student relationship of students who remained with the same teacher for two consecutive years in so-called looping classrooms (n = 98), to their peers in traditional one-year classrooms (n = 94). Contrary to prior research on the topic, this study used a strict protocol to ensure that teachers in looping and regular classrooms had similar profiles and valued similar educational practices. Results revealed that students who experienced looping had higher school grades in mathematics and writing and marginally better grades in reading compared to their counterparts schooled in annual classrooms. However, results regarding the teacher-student relationship were inconsistent and did not provide clear evidence in favour of either looping or annual settings. Overall, looping appears to be a quite simple and inexpensive measure likely to provide benefits on students' academic achievement. Such findings provide support for expanding looping programmes in elementary schools.