This study investigates how successfully English proficiency is enhanced in Grade 6 pupils using competency-based strategic intervention materials (SIM). The study primarily examines the issue of linking sentences using logical connectors in the third semester in the schools division of Baguio City. The authors employed a sample of 200 Grade 6 pupils and administered pre- and post-tests to assess the effect of the SIM. The z-test was employed to analyze the data, and purposive sampling specifically convenient sampling was performed to obtain the sample. The results demonstrate that the pretest and posttest scores vary considerably. The null hypothesis is accepted because the calculated F-value of 1.01 is less than the tabular F-value of 1.76 at a 5% level of significance, indicating that the evaluation of the SIMs quality-related effectiveness has significantly improved. This study highlights the following results: the implementation of competency-based intervention strategies face challenges such as limited availability and lack of localized materials a pretest in English 6 revealed specific skills that students struggle with, highlighting the importance of targeted intervention materials teacher assessments found that the competency-based intervention materials are high quality and meet standards for improving learning outcomes and comparing pretest and posttest scores, it was found that the use of these materials resulted in improved performance among students, indicating their effectiveness in enhancing learning outcomes. It was observed that learners enjoyed the learning process and made progress in their least-mastered abilities, in addition to the excellent academic results.