Middle school years are often affiliated with declines in students' motivation to learn (Eccles & Midgley, 1989; Maehr & Anderman, 1993). To counter this downward trend, research efforts should focus more on middle school students. In response to this call, the present study attempted to use achievement goal theory to understand seventh graders' motivation in running, a lifelong activity and an essential element of many middle school physical education/wellness programs. Specifically, two research questions were addressed: What are the relationships between achievement goals, students' persistence in running and their running performance? Are there any gender differences in these variables? Participants were (77 boys; 83 girls) seventh graders enrolled in physical education/wellness programs from two middle schools. They completed 5-point Likert scale questionnaires assessing achievement goals (mastery and performance) and persistence in running. All items were modified from published measures that demonstrated acceptable validity and reliability (Guan, Xiang, & McBride, 2006; Xiang, McBride, & Bruene, 2004). Participants also completed a timed 1-mile run as a performance measure. Finally, the researchers measured participants' height and weight. Preliminary analysis indicated no significant gender differences in height and weight. As a result, these two variables were excluded from subsequent analyses. Results of stepwise multiple regression analyses revealed for persistence in running, the mastery goal (β = .63) emerged as the only positive predictor and explained 40.1% of the variance. For the 1-mile run, both the performance (β = -.35) and mastery (β = -.20) goals emerged as negative predictors and explained 14.7% and 4.0% of the variance, respectively. A one-way MANOVA yielded a significant main effect for gender (p =.003; η2 =.11).The univariate follow-up tests indicated that, compared to girls, boys scored significantly higher on the performance goal and ran faster in the 1-mile run. Results of this study provide further empirical support that achievement goal theory can be used as a theoretical framework to understand middle school students' motivation and performance in the domain of physical activity. They also revealed the mastery and performance goals played different roles in students' persistence and running performance. Teachers need to be aware of this when attempting to enhance motivation, performance and learning among middle school students in their programs. Finally, gender differences observed on the performance goal and the 1-mile run time provided empirical support that gender is a significant factor in student motivation and performance.Keyword(s): gender issues, middle school issues