Background: Physical fitness and activity (PA) are related to academic performance, yet little is known about these relationships among Hispanic adolescents in low--socioeconomic status (SES), urban communities. Purpose: To evaluate the relationship of objectively measured PA and academic performance (AP) among Hispanic adolescents in one urban school district. Methods: One hundred sixty students were recruited from 6 Title I schools. Participants were instructed to wear a GT3X accelerometer for 5 weekdays. The district provided demographic and academic scores. Results: Pearson correlations yielded a weak and negative relationship existing between PA and AP, and the linear regression indicated that our predictor variables explained 15.2% of the variance, R[superscript 2] = 0.152, F(7,144) = 2.352, P < .001. Only the very vigorous PA intensity had a significant, negative effect on the relationship between PA and AP (ß = -1.241, p = 0.04). Discussion: Despite the positive findings in previous research regarding PA and AP, our data suggest that in urban schools, the benefits of chronic PA may be secondary to the effects of SES and time spent engaged with academics with regards to AP. Translation to Health Education Practice: Efforts to address inequalities should be embedded in health education lessons and physical activity programs for adolescents.A AJHE Self-Study quiz is online for this article via the SHAPE America Online Institute (SAOI) http://portal.shapeamerica.org/trn-Webinars