The current study aimed to adopt and assess the psychometric properties and measurement invariance of Grit-S among Omani and American students (N = 487) using Exploratory Factor Analysis (EFA) and Multi-Group Confirmatory Factor Analysis (CFA). The scale's construct validity was estimated by investigating its associations with achievement goal orientations (AGOs). EFA results suggested that a two-factor solution (i.e., perseverance of effort [G_PE] and consistency of interest [G_CI]) was the best factorial structure, explaining 47.74% and 51.02% of the variance in the Omani and American samples, respectively. The factors had good reliability coefficients in the two samples. Related to the intercultural differences, G_PE explained more variance among Omanis (31.02%) relative to American sample, whereas G_CI explained a larger proportion of variance among Americans (36.86%) compared with Omani sample. The first level of measurement invariance, configural invariance, was not supported, necessitating the investigation of the other levels of measurement invariance using a new sample. Grit correlated positively with mastery and performance-approach goals (r = 0.29 and 0.12, respectively) and negatively with avoidance goals (r = -0.25), supporting the scale's construct validity. These findings showed that Grit-S scale can be used as valid and reliable assessment tool to assess student interest and perseverance in the academic context in Arabic/Omani and American cultures.