Abstract—This study aimed to investigate the correlation between critical thinking skills and academic achievement in Biology through the implementation of problem-based learning-predict observe explain (PBLPOE) learning model. The study was conducted from February to June 2018 in the even academic year of 2017/2018. A correlational design was employed in this study. The participants consisted of tenth graders from Public Senior High School (SMAN) Number 5 in Bengkulu, Indonesia. The students’ critical thinking skills and academic achievement were measured using essay tests. The result of the regression analysis showed that there was a significant correlation between students’ critical thinking skills and academic achievement in biology, where Y=7.383 + 0.500x. The regression equation suggests that students’ academic achievement may improve as the students’ critical thinking increases. Therefore, it is advisable for the educator to promote critical thinking skills in the classroom in order to improve students’ academic achievement by, for example, implementing PBLPOE learning model.