The purpose of this study was to assess the grammar competence and English academic performance of first-year college students in Basilan State College. Stratified random sampling (n = 464) was carried out to sample the participants from each college within the institution. A standard grammatical test was used to assess the grammar skills of the participants. English grade point average (GPA) represented the students’ academic performance in English. Findings indicated that the first-year college students had limited skills in grammar mainly limited to familiar situations and had frequent problems in understanding and expression. Despite this, they still perform satisfactorily in their English classes. There was a significant moderate correlation between students’ grammar competence and overall academic performance. Education and health sciences students were highly competent compared to students from criminal justice, information and communication, and arts and sciences. Understanding the interactions among grammatical competence, academic achievement, and contextual factors may have significant effects on instructional strategies and direct the creation of focused interventions that will integrate students’ linguistic and intellectual growth.