Teachability perceptions reflect teachers' perceptions of students' cognitive-motivational behaviors, personal social behaviors, and school-appropriate behaviors. Teachers in schools with more students with a low socioeconomic status (SES) or in schools with more boys have been shown to perceive students as less teachable. It remains to be seen whether teacher characteristics, specifically efficacy or trust, buffer against lower teachability perceptions in challenging school contexts. A multilevel analysis was carried out on data of 1247 teachers in 59 Flemish schools (2012-2013). Lower teachability perceptions were found in low-SES schools and schools with more boys. Efficacious teachers perceived their students as teachable, but teacher efficacy did not buffer against lower teachability perceptions in low-SES schools or in schools with more boys. Teacher trust, on the other hand, does buffer lower teachability perceptions in schools with more boys. This finding demonstrates that trusting teacher-student relationships might be a key factor to overcome between-school differences in teacher perceptions.