The purpose of the study is to investigate the relationships between the science high school optional curriculum, knowledge coherence, and science academic success of first-year students at university. The correlational quantitative approach, the structured questionnaire, and a non-random sample of students were selected to be used in the study. The study found a high positive correlation between science high school optional curriculum and science academic success variables (r = 0.608). It is also revealed that the total variance of science academic success explained by knowledge coherence level is 33.8%, the other variance may be explained by other variables. The study found that high school optional curriculum, as well as knowledge coherence, predicts science academic success.