One perceived advantage of computer-based testing is that accessibility tools can be embedded within the testing format, allowing students with disabilities to use them when necessary to remove unique barriers within testing. However, an important assumption is that students activate and use the tools when needed. Initial data from large-scale computer-based testing suggest many students with disabilities are not using them; information is needed to understand why. Both computer skills and motivation are likely necessary for students to use accessibility tools; therefore, we explored whether prior computer use, math motivation, and test motivation predicted accessibility tool use on a national math test. We further explored the relationship between accessibility tool use and test performance. Accessibility tool use was relatively infrequent. Test motivation was weakly associated with text-to-speech use. Use of eliminate choice and scratchwork tools were weakly associated with performance. When combined with related empirical work, findings suggest a potential need to improve student test motivation and corresponding use of accessibility tools to improve validity of low-stakes test scores. However, given the weak relationships identified between tool use and performance, evidence-based math interventions are anticipated to be more helpful for improving math performance than mere promotion of accessibility tool use.