This quasi-experimental design study aimed to examine how exposure to supporting productive struggle teaching practice impacts students' conceptual understanding, procedural fluency, and strategic competence when solving high-demanding quadratic functions problem solving tasks. Results suggested that students in the supporting productive struggle teaching practice group performed significantly better than students who received facilitated instruction in every three strands of mathematical proficiency (i.e., conceptual understanding, procedural fluency, and strategic competence). By examining the effectiveness of supporting productive struggle teaching practice, this study offers insight into the conceptions and strategies teachers can implement in their classrooms to improve students' mathematical proficiency. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]