High school students in today's modern educational system are expected by educational authorities to demonstrate mathematical proficiency in both procedural fluency and conceptual understanding. Since the shift to Common Core Mathematics, the focus of mathematical pedagogy has shifted from procedural to conceptual, presenting difficulty for students and math teachers in this new domain of teaching and learning. Concurrent with this conceptual paradigm shift, student mobile phone increasingly infiltrated the classroom environment, causing unforeseen distraction and addictive behaviors in the classroom. The purpose of this study was to determine if a relationship exists between Problematic Mobile Phone Use (PMPU) and the two primary metrics of mathematical proficiency: procedural fluency and conceptual understanding. Utilizing a descriptive correlational design, this quantitative study employed statistical techniques including a combination of parametric and non-parametric multiple regression models for validity. Instrumentation included a research-based Student Mobile Phone Use Impression Survey(SMPUIS) to assess a stratified sample of educational leaders. The survey used a 5-pointLikert Scale for respondents to provide impressions of students' symptoms and related behaviors at their respective school site. The ten behaviors and symptoms were then placed in a regression model against the synthesized dependent variables. Results from both Pearson-r and Spearman's Rho statistical tests showed a significant negative association of PMPU with conceptual understanding, but no significant relationship with procedural fluency. Recommendations to practitioners include formulating a district-wide focus group on PMPU policy, and creating a professional development system for high school math teachers based on instructional strategies for conceptual learning targets. [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.]