Student mobility and its relationship to academic success have been researched since World War II with varied findings (Goebel, 1978). Establishing the relationship between mobility and achievement is difficult due to the fact that mobility is related to many factors. Mobility has been found to be prevalent among students who traditionally demonstrate achievement gaps (specifically students of low-income status) (Long, 1992; Smith, Fien & Paine, 2008). Mobility’s relationship to achievement is complex. Led by a single definition of mobility, admittance to more than one school in the given district over the period of one academic year, this research study sought to determine the effect of mobility on academic achievement. Specifically, the research focused on mobility’s effect on students classified as low-income and the effect of school mobility level on academic achievement of its students. This study used a quantitative design; student records were obtained for mobility data, and criterion referenced test scores in mathematics and language arts were utilized to measure academic achievement. Findings revealed that mobile students performed below non-mobile students, low-income status affected mobile students negatively, and mobility level of the school attended had a negative effect on the academic achievement of its students.