During the pandemic, the Department of Education used Self-Learning Modules (SLMs) for modular distance learning. The descriptive-evaluative design was used to assess the effectiveness of the SLMs of Grade 8 STE classes in Calbayog City's public junior high schools. Respondents were 8th-grade STE students at public high schools offering STE. A survey questionnaire was used to evaluate the SLM in eight dimensions: learning outcomes, content, resource materials, assessment, learning activities, clarity, cohesion, and feedback. Most STE students were female, at the right grade level, used online learning, and performed well in add-on subjects. SLMs were deemed effective learning materials. Age, sex, and first-quarter performance on SLMs like learning outcomes, learning activities, and assessment showed no significant differences. The evaluation showed no significant differences between learning modalities and SLM dimensions. In contrast, school is not a predictor of SLM's perceived effectiveness among students. Only age and sex correlated to SLM learning outcomes, assessment, cohesion, and resource materials. Since the SLM was evaluated as an effective learning material for add-on subjects in both learning modalities, the researcher recommends that teachers use the SLMs and that DepEd personnel like EPS in Science, school heads, teachers, and the Quality Assurance team continue assessing the SLMs in the STE program to ensure their effectiveness and quality. The researcher proposed a training design on teacher-made SLMs in the STE program using the ADDIE model as a capacity-building activity for teachers in developing and validating SLMs.