This study was conducted to determine which domains of inquiry-based science activities that significantly influence the students’ achievement of grade 10 learners. The study employed a quantitative, non-experimental method employing causal- effect. Mean, Pearson-r, and Regression Analysis were the statistical tools used to determine the level, relationship, and influence of each variable. The respondents comprised 332 grade 10 students from the four main secondary schools of District 1 in the Division of Compostela Valley, Province of Compostela Valley, for the School (...) Year 2018-2019. The findings of the study revealed a high level of inquiry-based science activities in terms of engagement, exploration, explanation, elaboration, and evaluation. This study also revealed that the level of students’ achievement was high in terms of cognitive development, laboratory skills, science process skills and understanding of science knowledge. The correlation between two variables of the study revealed significant relationship between inquiry-based science activities and students’ achievement. Lastly, the study revealed that exploration, explanation, elaboration, and evaluation are the domains of inquiry-based science activities that significantly influence students’ achievement. However, engagement appeared to be non-significant hence the null hypothesis is not rejected. (shrink)