Education has transformed in the past few decades with the introduction of online and blended learning. Many schools use technology to allow students to work in a blended classroom environment where they have face-to-face interactions and use online tools to enhance student learning. The existing literature suggests that the use of self-regulated learning (SRL) strategies impact student success. However, most of the research has been conducted at the college level, and limited research exists in the high school setting. This research investigated if a relationship exists between the four cognitive SRL strategies of rehearsal, elaboration, organization, and critical thinking and student success of students in a blended learning ninth-grade biology course measured by nine-week course grades. This quantitative study used regression analysis to determine if a relationship existed using Pearson Correlation Coefficients and whether SRL strategy could predict how a student will perform in the course. Participants working on a blended learning biology course for the first time were invited to respond to an adapted MSLQ questionnaire. Additionally, course grades were obtained by the end of the first nine weeks of the fall semester of the 2020-2021 academic school year. The data were analyzed using regression analysis, and it was determined that rehearsal and organization had a weak significant relationship to students' nine-week course grades based on this data. This research shows that student success can be impacted by how well students use SRL strategies when working in a blended learning environment. However, more research is needed to fill the gap in research in this area, and different instruments for measuring SRL strategies and student success may be necessary for more valid and reliable conclusions to be made. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]