This study investigated the effects of teacher-made video lesson aided instruction (TMVLAI) on students' science academic achievement test. It also examined if the learning activity of the students have been affected by TMVLAI.

This study utilized a quasi- experimental two-group pretest-posttest design involving Grade 8 online modality students at Holy Spirit National High School during the Fourth grading period of School Year 2020-2021. Two out of 11 sections were randomly chosen to be the participants of the study. One section was exposed to teacher-made video lesson aided instruction (TMVLAI) and served as the experimental group while the other section was exposed to conventional classroom instruction (CCI) and served as the control group. The researchers taught both the TMVLAI group and CCI group.

Two instruments were used for the data gathering - Science academic achievement test and an assessment on students' attitude toward teacher-made video lessons. Scores o students in both instruments were run and interpreted using the SPSS Software. All hypotheses were tested at significant level of .05. Students also answered open-ended questions to verify the results of the study.

The findings showed that there is no significance between two groups in terms of students' science achievement test. But the TMVLAI group got higher mean post-test scores than the CCI group. The learning activity assessment revealed that most students strongly agree and agree that they found the use of the teacher- made video lesson beneficial to their learning most especially if they are not able to attend their synchronous class.

Thus, recommendations for the utilization of video lessons is suggested as well not only for online modality classes but also for the modular modality classes.
Keywords: teacher-made, video lessons, effectiveness, academic achievement, online modality