Defined as a combination of perseverance and passion for long-term goals, grit has been hypothesized to be as important as talent in determining the success of students, adding incremental predictive validity for achievement criteria above and beyond natural or inherent ability. In this study, we tested this hypothesis by comparing the effects of second language (L2) aptitude and L2 grit on L2 achievement. We also explored how age, L2 learning experience, and gender of the students influenced their L2 aptitude and L2 grit levels. The findings showed that L2 aptitude and L2 grit had similar, positive effects in predicting language achievement measures. Moreover, some aspects of the students' language aptitude and L2 grit were susceptible to change as they aged and gained more L2 learning experiences, but their gender played no reliable part in this regard.