The continuous development of new platforms and environments for technology-enhanced learning emphasizes the increasing importance of research in educational technology acceptance (ETA). Responding to this need, the unified theory of acceptance and use of technology (UTAUT) proposes a major ETA model. However, the UTAUT has been so far validated only in restrained contexts. The ongoing internationalization of education calls for extending ETA research and the UTAUT across national and professional boundaries. Therefore, this study aims at cross-cultural validation of the UTAUT by examining a large sample (N = 4,589) of educational technology users from three European countries, Germany, Romania and Turkey. As a first conclusion, the UTAUT questionnaire displays adequate validity, reliability, and measurement equivalence across cultures, which further enables UTAUT-based comparisons of the cultural groups. Secondly, the effect of technology use intention on the actual use behavior proves to be extremely weak. Several possible explanations are proposed along with suggestions for future research. Thirdly, for the first time in ETA research the cultural sample diversity allows the verification of correlations between acceptance and culture. Thus, this study makes headway in the integration of culture (sensu Hofstede) in the UTAUT by suggesting effects of power distance, individualism, masculinity, uncertainty avoidance and long-term orientation on performance and effort expectancy, perceived social influence, computer anxiety, technology use intention and actual use behavior. Fourthly, for educational practice the presented results suggest several ways of anticipating and supporting ETA in multicultural user groups.