Grade retention is widely used in Macao at the elementary and secondary levels. While many teachers and students believe retention gives low-performing students the opportunity to catch up, there is little empirical evidence to support such a claim. Using Programme in International Student Assessment 2009 (pisa, 2009) data, we examine the effect of grade retention on students' learning time, learning strategy, metacognition, and academic achievement. We also analyze the influence of school policies to determine the net effect of retention. Our findings suggest that, contrary to conventional thinking, grade retention has a highly negative effect on the above factors. Students who repeated a grade did not benefit from this second chance, but rather were substantially held back in their learning trajectory. We suggest that schools in Macao shift their focus to designing programs that will help students with greater needs, rather than focusing exclusively on identifying such students.