Using a dot‐probe detection task, this longitudinal study investigated whether adolescents show an attentional bias for academic stressors at the beginning of the school year (T1), and if such allocation of attention interacts with classroom climate (CC) to predict grades and socioemotional functioning at the end of the term (T2). Among 133 eighth‐graders, the majority showed a perceptual bias toward academic threats. Regression analyses indicated that a greater bias at T1 predicted lower grades and more socioemotional problems at T2, and that CC moderated these relationships. Students perceiving low CC and displaying greater attentional bias reported lower grades and more socioemotional problems. Teachers may promote a positive CC to prevent the negative effects of a biased attention on youths’ school adjustment.