The use of standardized testing to evaluate academic achievement is a widely debated topic. Despite controversies, standardized testing is used in all educational levels from elementary school to college entrance examinations. One of the ethnic groups particularly affected by this is the Mexican-origin population. An integrated model (individual, family, peer, and institutional factors) is used to enhance our understanding of the disparity in standardized mathematic test scores between Mexican-origin and White students. Findings show that socioeconomic status (SES) explains the majority of the gap in test scores. However, Whites reap more favorable returns to SES than do students of Mexican origin. Furthermore, if Mexican-origin students were to resemble their White peers in terms of generational status the gap in scores would widen. (Contains 2 tables and 3 notes.)