The main purpose of this study was to investigate English second language(ESL) teachers' perceptions about learner self-assessment in the secondary school. The study also examined the factors that might influence the perceptions that teachers hold about self-assessment. The participants of this study were 163 ESL teachers who are teaching at secondary schools in Gauteng Province; they were from 94 randomly selected schools. The data was collected through questionnaires and the response rate was approximately 53%. The literature review was utilized to identify the main perceptions. The studies led to a 57-item teachers' perceptions of learner self-assessment questionnaire based on the following main perceptions: the value of self-assessment in the teaching and learning processes, the use of self-assessment as an alternative assessment technique in English second language learning, the accuracy and reliability of self-assessment and the role of teachers in the effective implementation of self-assessment in their classrooms. The data for the study were analysed using quantitative techniques. the findings for the study showed that teachers have a strong feeling about the value of learner self-assessment; they showed that it helps in the improvement of teaching and learning. The results also indicated that teachers agree that self-assessment should be used in English second language teaching as an alternative form of assessment as it enhances learners' linguistic skills. Teachers perceive that they have an important role to play in ensuring that the implementation of self-assessment becomes successful in their classrooms. However, some have indicated that learners are not objective enough when assessing themselves and therefore the results derived from self-assessment cannot be reliable and accurate. Teachers' perceptions correspond with their classroom self-assessment practice because most of them also indicated that they employ self-assessment to enhance learners' performance. Majority of teachers also indicated that factors such as class size, availability of materials, teacher professional training and development, formal teacher training, years of experience, classroom experience with self-assessment, and time available for self-assessment played a significat role in influencing their perceptions. The conclusions were drawn from the results and the recommendations were made for further research. The limitations of the study were also discussed.