Positive psychology, which has emerged as a major force since the turn of the 21st century, focuses on the constructive effects of positive emotions (Fredrickson, 2001; Seligman & Csikszentmihalyi, 2014). The purpose of this study was to establish a measure of positive psychology in language learning. To this aim, the researchers developed a 54-item questionnaire after conducting semi-structured interviews with teachers. The questionnaire was piloted with 369 EFL learners. The results of running exploratory factor analysis indicated that nine items did not show high factor loadings. Therefore, the questionnaire was revised and administered to 385 participants. The results also showed that the six factors extracted by the principal axis factoring (PFA) accounted for 52.08 percent of the variance. The confirmatory factor analysis run on the data showed construct validity of the "inventory of positive psychology in language learning" or ''IPPLL.'' Moreover, non-significant chi-square, ratio of chi-square over the degree of freedom, the root mean square of error approximation (RMSEA), and Holeter index of sampling adequacy all indicated that the model showed a good fit.