Changing schools impacts students’ achievement, educational attainment, and their relationships with peers and teachers. Mobile students tend to have lower grades and test scores, experience grade retention more frequently, and are more likely to drop out of school (Rumberger, 2003; South, Haynie, & Bose, 2007). As the evidence of student mobility’s negative consequences grows, understanding the influence of mobility on schooling in Texas and the Houston area becomes increasingly important. Before examining mobility’s impact, however, we have to understand its prevalence. This research brief offers an initial, descriptive look at summer mobility, or mobility that takes place between school years.