This paper addresses perceptions and implications of teacher evaluation by Arab school principals in an era of accountability. Analysis of semi-structured interviews with 26 Arab principals showed that teacher evaluation as a strategy keeps the school accountable in an era of reform. Additionally, most principals recognize the tool's possible uses to improve the level of teaching and learning in an effort to increase students' achievements. Nevertheless, it was found that when teacher evaluation is the key tool, the principals' efforts to develop the teaching abilities of excellent teachers decrease. This study offers conclusions as to the (socio-cultural, perception-based, and personal-professional) factors that inhibit the implementation of a valid and reliable teacher evaluation process.