This retrospective quantitative study examined the relationship between visual-spatial reasoning abilities, as measured by the matrix reasoning and block design subtests of the Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV), and geometry and math performance, as measured by geometry and overall math scores from the Massachusetts Comprehensive Assessment System (MCAS). Recent research in the field of math disability (MD) has sought to more clearly define the various, distinct cognitive profiles of students with MD. This has required an examination of the separate types of math problems that students face in the classroom, as well as an examination of the various cognitive abilities that underlie these separate groups of math problems. Several researchers have identified three areas of difficulty which could each lead to MD, including, mastering and recalling basic number facts (number sense), language impairments, and visual-spatial difficulties (Garnett, 1998; Geary, 2004; National Center for Learning Disabilities, 2006; Wright, 1996). Other researchers, including Kovas, Petril, and Plomin (2007), have identified five distinct mathematical domains: mathematical applications, understanding numbers, computation and knowledge, mathematical interpretation, and non-numerical processes. Students with MD tend to struggle with one or more of these domains. The present study helps to isolate impaired visual-spatial reasoning ability as an underlying cause of MD in students who struggle with geometry in particular, and math in general. Subjects were 31 middle school students from a public school in western Massachusetts, approximately 50% male and 50% female. It was predicted that lower matrix reasoning (MR) and block design (BD) scores would predict lower scores on MCAS geometry and MCAS math. A Pearson r revealed a significant positive correlation (0.479) between BD scores and MCAS math scores, a significant positive correlation (0.373) between MR scores and MCAS geometry scores, and a significant positive correlation (0.479) between combined WISC-IV subtest scores (MR+BD) and MCAS math scores. An independent groups T-ratio revealed no significant relationship between the MCAS math or MCAS geometry scores of three groups of participants; those who scored below the mean on one, both, or neither of the WISC-IV subtests. A Spearman r revealed significant positive correlations between participants' block design rank and MCAS math rank (0.431), between MR rank and MCAS geometry rank (0.369), and between participants' combined WISC-IV subtest score rank (BD plus MR) and their rank-ordered MCAS math results (0.423). The data implicate visual-spatial ability as a factor underlying success in math and geometry. [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.]