As a personality trait, second language (L2) grit--a combination of perseverance and passion for L2 learning--has recently been proposed as a meaningful predictor of learners' motivational behavior and L2 achievement. The results of a growing body of empirical studies carried out in various L2 contexts have substantiated the power of L2 grit in predicting L2 success. In this paper, we contend that grit and its potential effects on L2 outcomes should be conceptualized and measured in a domain-specific fashion. We argue that a domain-specific measure of grit enhances its predictive and construct validity and better captures its differential effects in various domains and across languages. We then briefly review the findings of existing grit research in L2 contexts with respect to their domain-general versus domain-specific conceptualization of grit. Finally, we conclude the paper by discussing several issues raised against domain-general grit and discuss their potential relevance to domain-specific grit research in the context of L2 learning.