Personality is one of the important variables for predicting student academic success. The purpose of the research is to examine the Big Five personality test as a predictor on the academic achievement of State Islamic Senior High School students in Indonesia. This research used a quantitative method which used a survey of the Big Five Personality Test and learning achievement on 5 subjects. The subjects of this study were the 2145 sample students of 23 State Islamic Senior High School of Insan Cendekia (SISHS-IC) around Indonesia. The results of this study indicate that all dimensions of Big Five Personality traits; openness to experience, conscientiousness, extraversion, agreeableness, and emotional stability have a significant effect as predictors of students' academic achievement. While in parts of each dimension, the most significant predictor of students' academic achievement is the emotional stability and openness to experience. These findings are very important for teachers and schools to pay much more attention to emotional stability and openness to experience as predictors of student academic achievement.