Teachers' teaching self-efficacy and teachers' feelings of negative affect may be associated with students' academic achievement; however, little is known about how these factors directly affect adolescent students' math and reading achievement. The eighth-grade wave of the Early Childhood Longitudinal Study data was used to investigate teacher variables on students' achievement. This United States nationally representative dataset was used to investigate the associations between teachers' teaching self-efficacy and teachers' burnout on eighth-grade students' math and reading achievement. The eighth-grade sample had 9725 students within 9128 teachers. A structural equation model indicated that teachers' high teaching self-efficacy did not predict students' achievement, yet teachers' negative affect was a negative predictor of the students' reading and math achievement. Teaching self-efficacy and negative affect were negatively covaried, indicating that teaching self-efficacy can potentially provide a buffer against teacher burnout and can inform future interventions to support and protect teachers from career negative affect. Indications for supporting teachers are discussed.