Mathematics anxiety (MA) is a prevalent issue known to impact individuals of all ages around the world. It negatively impacts learning, performance, choice of program of study, and career choice. As a focus of research for decades, the impact of mathematics anxiety has been approached mainly from a pedagogical or cognitive perspective. While these areas have provided a wealth of knowledge, interestingly, less research has approached this anxiety from a clinical perspective, and little is known about how best to treat MA. This dissertation brings together current findings on MA as well as current findings from clinical psychology to provide a clinically relevant approach to the math-anxiety-math-performance relation to inform intervention. Specifically, this dissertation focuses on the role of transdiagnostic factors of anxiety in MA. Beginning with an in-depth review of the current understanding of how MA negatively impacts performance and a review of four transdiagnostic factors: Emotion Regulation (ER), Emotional Distress Tolerance (EDT), Anxiety Sensitivity (AS), and Intolerance of Uncertainty (IU) in Chapter 1. Chapter 2, the first of two research papers, explores the moderating effects of the four transdiagnostic factors of anxiety in the math-anxiety-math-performance relation by assessing the influence of anxiety on performance by measuring two types of anxiety experienced during math tasks (i.e., state anxiety and traditional mathematics anxiety) and the impacts of these anxiety experiences on two types of math tasks (i.e., math facts, and math computation). Chapter 3 delves into developing a new measure of MA, the Subjective Experience of Math Anxiety (SEMA). This study explores the measure's psychometric properties, including internal consistency and validity. A shift away from the traditional measures of MA serves to provide a more clinically relevant way of measuring MA to inform treatment. Finally, Chapter 4 provides an in-depth review of the malleability of transdiagnostic factors, and the treatments known to do so. It also serves to identify potential treatments that could be adopted for use with mathematics anxiety.