Several researchers have investigated different factors which are found responsible for students' mathematics achievement. This study examined achievement motivation, locus of control and study habits as predictors of mathematics achievement of freshman students taking non-board examination programs at a certain state university in Southern Luzon, Philippines. In this descriptive-correlational research design, purposive sampling technique was used to select 258 participants enrolled in the subject mathematics in the Modern World. Four sets of research instruments were used for the data collection: namely, mathematics Achievement Motivation Scale, Locus of Control Scale, mathematics Study Habits Inventory and the teacher-made mathematics Achievement Test. The results showed that most students have average achievement motivation, internal locus of control, desirable study habits and average mathematics achievement. The results also revealed that there was a significant relationship between achievement motivation and mathematics achievement and achievement motivation was found to be the only predictor of mathematics achievement. This indicates that achievement motivation is effective in enhancing mathematics achievement. Students' achievement motivation will increase to high level if given the right remediation. Hence, high achievement motivation can predict high mathematics achievement.