The problem and the aim of the study. Classroom Assessment (CA) is as part of School-Based Assessment (SBA), which reflects students' achievement in mastering Learning Standards. However, the issue of teacher competency is a significant concern in CA to ensure quality CA implementation. It is important for subject teachers to engage in self-evaluation and lifelong learning to enhance their assessment skills. While selfassessment is crucial for Home Science teachers, there is currently no standardized instrument available for this purpose. This study aims to develop a self-assessment instrument to evaluate the competency of Home Science Teachers in classroom assessment. Research methods. This study utilizes qualitative and quantitative research methods. Qualitative research method is employed during need analysis and requirement analysis phase for self-assessment instrument development using semi-structured interviews with three experts in Home Science. With these data, the self-assessment instrument, in form of a questionnaire, is designed and developed. After the instrument development is completed, expert validation is obtained using qualitative and quantitative approach, namely using semi-structured interview with three experts and questionnaire respectively. A 10-likert scale questionnaire is distributed to the same experts to obtain the percentage of expert agreement to determine content validity of the developed instrument. Results. The achievement of expert validity of each item in the developed instrument indicates the appropriateness of all items contained in the instrument, where 20.5% of the items obtained over 80% agreement score and 79.5% of the items obtained over 90% agreement score. The overall agreement among experts achieves 90.6%, which is above the acceptable level of agreement. Hence, the result indicates that the instrument is appropriate for Home Science teachers to evaluate their competency in classroom assessment. Conclusion. In conclusion, a self-assessment instrument to evaluate the competency of Home Science Teachers in classroom assessment has been developed. With this instrument, Home Science teachers can execute their self-assessment and hence can identify their training needs in classroom assessment. As a result, competent teachers will be able to execute classroom assessment effectively and support one of United Nation’s SDG namely quality education.