Researchers of KU Leuven, a large Belgian university, were invited to complete a bespoke questionnaire assessing their attitudes toward research integrity and the local research culture, with specific emphasis on the supervision of junior researchers. A total of 7,353 invitations were sent via e-mail and 1,866 responses were collected (25.3% response rate), of which 1,723 responses are reported upon here. Some of the findings are relevant to the broader research community. Whereas supervisors evaluated their supervision of junior researchers almost unanimously as positive, fewer supervisees evaluated it as such. Data management emerged as an area of concern, both in terms of reviewing raw data and of data storage. More female than male professors emphasized open communication and supported their supervisees’ professional development and personal well-being. At the same time, fewer female professors felt safe to speak up than male professors. Finally, researchers who obtained their master’s degree outside Europe evaluated their supervision and KU Leuven’s research culture more positively than researchers with a master’s degree from KU Leuven. The results of the survey were fed back to the university’s board and several bodies and served as input to update the university’s research policy. Faculties and departments received a detailed report.