Recent results from large-scale testing programs (e.g., the ACT® test, Programme for International Student Assessment) show declines over time in high school students' mathematics performance. Such declines can be concerning for many, including students, parents, and educators. Several factors could be related to mathematics performance declines, including the COVID-19 pandemic, technology distractions in mathematics classes, and mathematics anxiety. The purpose of this study was to explore (1) the relationship between technology distractions in mathematics classes, specifically those resulting from the use of smartphones, and performance on the ACT mathematics test and (2) the relationship between mathematics anxiety and performance on the ACT mathematics test. In addition, to determine whether smartphone distractions and anxiety might be related to performance in subjects other than mathematics, this study explored relationships among smartphone distractions in science classes, science anxiety, and performance on the ACT science test.