Blackwell et al. (Child Development 78(1):246-263, 2007) tested a motivational model of achievement in which an incremental theory of intelligence leads to learning goals and positive effort beliefs, which leads to fewer ability-based, helpless attributions, and more positive strategies, which leads to improved grades. In the present study, we tested this model by using a different population, using domain-specific items, comparing the results across gender, including "interest" as another variable in the model, and assessing the impact of achievement as an antecedent and outcome variable in the model. Participants included 163, mostly White, ninth-grade Algebra students from a suburban school in southwest Virginia, USA. We established that the model had a relatively good fit to the data and all paths were statistically significant when achievement was used as both an antecedent and outcome variable. The standardized path coefficients were consistent with those reported by Blackwell et al. and the model was invariant across genders. Furthermore, we documented that interest could be included as another mediating variable in the model. The results of this study provide evidence to support the validity of the relationships between the constructs in the Blackwell et al. model for the population examined.