This study investigates the primary factors influencing school achievement during the COVID-19 pandemic from students' perspectives. The pandemic exacerbated educational inequalities, emphasizing the essential role of teacher effectiveness in boosting student achievement and the significant impact of remote learning challenges. Using focus groups with 74 Portuguese students, this study explores how teacher quality, student engagement, and personal effort contribute to academic success. Results reveal that students credit their success to effective teachers but take personal responsibility for poor performance. Despite literature suggesting the importance of educational leadership, students perceived daily interactions with teachers as more influential. The transition to online learning posed significant challenges, including access to materials and technical issues, which affected student engagement and well-being. Students expressed the need for better workload management and varied assessment methods.