Empirical research provides strong support for the trichotomous and 2 x 2 achievement goal models (Elliot, 1999; Elliot & McGregor, 2001). Additionally, research shows that the 2 x 2 model provides a better fit to the data than the trichotomous model. However, both models were tested in college classrooms. Few studies have examined the reliability and validity of these testing scores when used with high school students in athletic classes. The purpose of this study was to examine whether the trichotomous and 2 x 2 models developed in university undergraduate classrooms were appropriate in high school athletic classes and whether the 2 x 2 model might represent a better fit to the data than the trichotomous model. A total of 171 high school athletes (123 boys, 48 girls) served as participants. They completed both the trichotomous and 2 x 2 achievement goal scale-athletic programs (AGS-AP). The 2 x 2 AGS-AP, adapted from Elliot and McGregor (2001), consists of 12 items reflecting four achievement goals: mastery-approach, performance-approach, performance-avoidance, and mastery-avoidance. The trichotomous AGS-AP consists of 18 items adapted from Elliot (1999) and reflects three achievement goals (mastery-approach, performance-approach, and mastery-avoidance). The format for all items is a 7-point Likert-type scale, ranging from 1 (not at all true for me) through 7 (very true for me). Confirmatory factor analysis (CFA) was employed to examine the construct validity of both the 2 x 2 and trichotomous AGS-AP. Multiple fit indices including comparative fit index (CFI), Bentler and Bonnett's Non-normed fit index (NNFI), goodness of fit index (GFI), and root mean square error of approximation (RMSEA), assessed the adequacy of two models. The results showed that the 2 x 2 AGS-AP represents an adequate fit to the data (CFI = .93, GFI = .90, NNFI = .91, and RMSEA = .07). Cronbach's alpha coefficients for the mastery-approach, performance-approach, mastery-avoidance, and performance-avoidance goals were .79, .68, .80, and .60, respectively, indicating acceptable internal consistency. However, CFA analysis revealed that the trichotomous AGS-AP provided a poor fit to the data (CFI = .70, GFI = .69, NNFI = .65, and RMSEA = .12), although Cronbach's alpha coefficients indicated acceptable reliability (mastery goals = .84, performance-approach goals = .79, and performance-avoidance goals = .65). The results of this study suggest that the 2 x 2 model provides a reliable and valid measure of achievement goals for this population of high school athletes compared to the trichotomous model. Keyword(s): assessment, athletics/sports, high school issues