To examine differences between sequences of secondary science courses on achievement on science high stakes exams, a purposive quantitative research design was utilized in this study. A short survey was sent out to public high schools in the state of Missouri that asked to identify their main science course sequence. In addition, participants were asked to indicate if they had altered their science course sequence between the years of 2012 and 2017. This data were compared to their average building science American College Testing (ACT) score for the 2015-2016 and 2016-2017 school years in which all 16-17-year-olds in the state were required to take the exam. The analysis of the results found no connection between science course sequence and performance on the science section of the ACT for either year. In addition, it was found that schools that indicated that they altered their science course sequence had no difference in performance on the science portion of the ACT. Further research is needed to determine if there are any benefits to altering a science course sequence.