The paper presents the development and the results of testing a new tool Integrative Intercultural Competency Questionnaire, aimed at studying the ability to function effectively in an intercultural communication context. The questionnaire was created on the basis of the integration of 52 constructs from 14 methods for measuring intercultural competence. The research (N = 1024) revealed that the tool contains four subscales: Intercultural Stability (individual personality characteristics that allow a person to be resistant to stressful situations of intercultural communication), Intercultural Interest (desire to communicate with people from other cultures, interest in culture and cultural differences), Lack of Ethnocentrism (respect and acceptance of cultural diversity) and Management of Intercultural Interaction (wide range of communication skills, important for intercultural communication). The subscales have good internal consistency and invariance with some limitations in comparing people of different ages. The research also demonstrated the external validity of the tool. The subscales of the Integrative Intercultural Competency Questionnaire are positively associated with the Extended Cultural Intelligence Scale. People who demonstrate higher rates on individual scales of the questionnaire are distinguished by a large number of specific intercultural achievements. Correlations of the subscales with indicators of adaptation of foreign students, emotional burnout, and self-efficacy among teachers working in a multicultural environment are observed.