The present paper proposes developing and validating the Boredom Intolerance Scale (BIS) – the first and only measure assessing the degree to which individuals are able to stand the experience of boredom. Across three studies (N = 1397), the psychometric properties of the BIS are presented. Exploratory factor analysis, implemented in Study 1, suggested a unidimensional and 6-item structure with high reliability. Study 2 ratified the emerged structure by using a confirmatory factor analysis. Corroboration of the measure's robustness was provided by a multigroup CFA, which yielded evidence for the gender invariance of the BIS Italian version. Study 3 validated the English version of the BIS, indicating a robust factor structure with high reliability and invariance across participants' gender. Study 3 also proved the BIS's invariance across English and Italian versions. Construct validity was examined across Studies 2 and 3, yielding significant associations of the BIS with measures of trait and state boredom, relaxation sensitivity, neuroticism, anxiety, anger, impulsiveness, depression, life satisfaction, and purpose in life. These findings suggest that the BIS is a psychometrically sound measure with possible implications for researchers and practitioners.