Spatial ability is a multifaceted construct with demonstrated ties to success in mathematics and gesture production. Recent empirical work has also begun investigating whether targeted interventions for spatial ability can transfer to mathematics but are often limited to specific populations and specific math outcomes. Spatial anxiety has been shown to be negatively associated with the ability to access and utilize spatial skills. However, little is known about the interplay between spatial ability, spatial anxiety, and gestures in mathematics. This dissertation describes a guiding framework for researching spatial ability in mathematics before describing four studies to investigate the relationships between these constructs. These studies cover a multitude of mathematics domains, populations, and methods of analysis, including an experimental study on adult's performance on standardized mathematics outcomes, an analysis of existing data from a longitudinal study on children's fraction knowledge, and an experimental study on undergraduates' geometric thinking, and a randomized control study on undergraduates' geometric thinking and gesture production following a short spatial intervention. Several findings emerged. First, specific spatial sub-categories could be more critical for success on different math tasks, and spatial anxiety scores predict spatial and math ability scores. Second, spatial anxiety may moderate the relationship between spatial ability and both geometric thinking and representational gesture production. Third, spatial-based Tangram tasks may increase the likelihood of transformational proof and dynamic gesture production. These findings will inform future classroom-based spatial interventions and studies exploring the links between mathematics, gesture, spatial ability, and spatial anxiety. [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.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]