Introduction: In high-income countries around the world, there appears to be an inverse association between educational attainment and obesity. However, the literature about this association in Spain remains disorganized and disparate. Material and Methods: We systematically reviewed peer-reviewed English- or Spanish language studies of this association in Spain from 10 databases from all periods of time available. Results: Our search identified twenty-four studies. In both nationally representative and subnational studies, women with less education had higher odds of obesity than their more educated counterparts. Men, despite exhibiting greater variability in the education-body weight relationship, also demonstrated a similar social patterning of body weight in many studies, with those at lower levels of educational attainment having higher odds of obesity relative to their more-educated counterparts. These associations in men and women were fairly consistent across time and place, though some regional variations did exist. Discussion and conclusions: We encourage future researchers to move towards more meaningful, unbiased estimates of the association between educational attainment and obesity by measuring height and weight with physical exams, controlling for a more robust set of possible confounders, and exploring potential modifying factors of the association. Additionally, when possible, we encourage researchers to employ prospective study designs that facilitate causal inference with respect to this association.