The purpose of this study was to examine (a) the effects of three curricular activities on students' situational motivation (intrinsic motivation [IM], identified regulation [IR], external regulation, and amotivation [AM]) and physical activity (PA) levels, and (b) the predictive strength of situational motivation to PA levels. Four hundred twelve students in grades 7-9 participated in three activities (cardiovascular fitness, ultimate football, and Dance Dance Revolution [DDR]) in physical education. ActiGraph GT1M accelerometers were used to measure students' PA levels for three classes for each activity. Students also completed a Situational Motivation Scale (Guay, Vallerand, & Blanchard, 2000) at the end of each class. Multivariate analysis of variance revealed that students spent significantly higher percentages of time in moderate-to-vigorous PA (MVPA) in fitness and football classes than they did in DDR class. Students reported higher IM and IR toward fitness than DDR. They also scored higher in IR toward fitness than football. In contrast, students displayed significantly lower AM toward fitness than football and DDR. Hierarchical Linear Modeling revealed that IM was the only positive predictor for time in MVPA (p = 0.02), whereas AM was the negative predictor (p less than 0.01). The findings are discussed in regard to the implications for educational practice. (Contains 3 tables.)