Previous research has demonstrated a link between spatial and math skills. However, little research has examined this relation longitudinally. The present study examines the development of and reciprocal relations between spatial and math skills in elementary school students. We administered two spatial tasks and a math task to 312 first- through third-grade students who were tested in the spring for three consecutive school years. Linear growth models showed increases for each skill across the three school years. A random intercepts cross-lagged panel analysis indicated that controlling for task-specific (i.e., autoregressive) growth, there was a relation between spatial visualization/mental rotation at Year 1 and math performance at Year 2. In addition, math scores in Year 2 predicted Year 3 spatial visualization/mental rotation skills as well as Year 3 spatial perception skills. Further, there were significant differences in task performance depending on grade in school, and there were gender differences in spatial perception and sometimes math performance. Thus, we find some evidence for reciprocal relations between spatial and math skills over development, but our results suggest that the particular type of spatial skill measured is important to consider in studying these relations. (PsycINFO Database Record (c) 2019 APA, all rights reserved).