Insights into emergence and influence of cultural diversity are becoming more important, due to an ongoing upward trend towards diversified societies. Yet, there is little scientific evidence on the specific attitudes of managers regarding cultural diversity, especially for technical and scientific professions. The present qualitative study examined the experiences, social influences, and competencies of managers in the STEM sector, which are important for managing cultural diversity. The results show that only a few of the respondents were aware of the opportunities and risks of cultural diversity and the specific challenges for people with a migration background. Furthermore, the respondents´ own experiences and sensitivity, their own identification with the company and previous diversity measures in the context of the companies ‘position seemed to be relevant for the formation of attitudes. The respondents also stated a lack of interpersonal and intercultural competencies among junior managers, which should be addressed by both companies and educational institutions.