Objectives To study the frequency of observed cases of disciplinary law complaints concerning transgressive behaviour in Dutch healthcare by analysing disciplinary cases handled in Dutch disciplinary law. Design Retrospective review of complaints in the Dutch disciplinary law tribunals from the period 1 January 2015 to 1 January 2020. Setting Dutch healthcare. Method Descriptive retrospective study. All judgements at regional disciplinary tribunals in the first instance from the period 1 January 2015 to 1 January 2020 concerning transgressive behaviour were investigated. The following was studied: year of judgement, number and nature of complaints, type of complainants, profession of defendant. Results Over the study period, 139 complaints about transgressive behaviour were handled, 90 of which involved sexual behaviour. 66/139 complaints were submitted by patients themselves (47.5%). Most complaints were directed against physicians (44.6%; n=62), followed by nurses (30.2%; n=42), psychologists (11.5%; n=16) and physiotherapists (7.9%; n=11). 80.6% of the complaints were directed against a male healthcare professional (OR 4.25; 95% CI 1.7590 to 10.2685; p=0.0013). 104/139 of the complaints originated from an outpatient work setting and about half of the complaints originated from mental healthcare. Of the 90 disciplinary cases in which the complaint was related to sexually transgressive behaviour, 83.3% (n=75) were ruled to be substantiated (5 of which partially) with a measure imposed in all cases: 6 formal warnings (8%), 11 reprimands (14.7%), 10 denials (partial suspension) (13.3%), 26 temporary suspensions (34.7%) and 22 cancellations of the licence to practice (29.3%). Conclusion This study describes jurisprudence of disciplinary cases about transgressive behaviour of healthcare professionals in the Netherlands. The results of this study can be used to monitor trends in observed cases of transgressive behaviour.