This research aimed at determining the level of performance of state senior high school (Sekolah Menengah Atas Negeri abbreviated as SMAN) teachers aged 56 years and older. The research population was all SMAN teachers aged 56 years and older in Banda Aceh Municipality, Districts of Aceh Besar, Pidie and Pidie Jaya. Performance assessment instruments developed were tested for construct validity by factor analysis techniques, and reliability estimated by using Cronbach Alpha formula. The levels of teacher performance are grouped in five categories as: very high, high, medium, low and very low. The results show that the five components of the SMAN teachers' performance aged 56 years and older were at "very high" category, namely: learning strategies, mastery of materials, classroom management, communication between teachers and students, and teaching techniques. Another performance component, assessment of students learning outcomes was at "medium" category. So, it was found that the performance of SMAN teachers aged 56 years and above was very high.