College readiness is one of the concerns of both students and universities nowadays, and when it comes to readiness, we speak about aptitude. On the other hand, Academic achievement plays an important role in determining students’ aptitude ability. It is a manifestation whether a student maximizes his aptitude ability in order for him to have an excellent academic achievement. This empirically-driven study aims to look on how aptitude subscales, namely, verbal reasoning, quantitative reasoning, abstract reasoning, and spatial reasoning affect academic performance of the students. Seven hundred sixty-one (761) first-year college students composed of 350 males and 411 females, who took the Assessment for College Potential, were involved in the study. The research design used descriptive-correlational. Data analysis utilized were Pearson Product Moment Correlation to look for the relationship of the variables, and Stepwise Linear Regression Analysis to determine which of the variables under Aptitude highly predicts Academic Achievement. The results revealed that (1) a significant correlation between Student’ Aptitude Scaled Ability Score and Academic achievement (r=.597) and (2) the highest predictors for academic achievement for this group are Verbal Reasoning (sig.=000) and Quantitative Reasoning (sig.=000).