Assessment is very important in the learning and instructional processes. Equally important is the use to which assessment results are put. Use of student achievement scores (SAS) as a basis for assessing the teacher’s instructional competence or effectiveness is one of the controversial approaches to teacher evaluation. This article examined the issues characterizing the use of SAS as a basis of teacher assessment, and presents research results from Nigeria and abroad on the attitude of teachers to this approach of assessing teachers. The research findings from abroad were extracted from the literature. The research in Nigeria sampled 480 secondary school teachers in Akwa Ibom State using stratified random sampling technique. The instrument for data collection was a questionnaire with a reliability estimate of .94. Three hypotheses were tested. The results showed that secondary school teachers displayed a significantly negative attitude to this teacher assessment approach; that this attitude was not significantly influenced by the professional status of the teachers; and that this attitude, when the purpose of teacher assessment is summative, is significantly more negative than the attitude when the purpose of teacher assessment is formative. It was concluded that Nigerian teachers are not different from their counterparts abroad in their showing disdain or condemnation to the use of student achievement scores as indicators of teacher’s competence, performance or effectiveness. Therefore, great care is required in the use of assessment results in our schools, especially in attempts to blame teachers for poor academic performance of learners.