This fifth and final in a series of 5 articles in the context of the 2017 Kies-voor-Tanden study presents the results for 23-year-olds. 21% of the 23-year-olds had flawless permanent teeth. In 2017, there were still differences in oral health among the socio-economic (SES) groups, to the advantage of the high SES group. The oral health of the low SES group had shown some improvement in the previous 6 years, while this was not the case within the high SES group. The preventive dental behaviour of 23-year-olds was not optimal and the knowledge about the dental insurance system was poor. Conclusion: the oral health of 23-year-olds had partly improved, partly stagnated. Since not everyone will be able to access information through oral care professionals, other ways of providing information to them must be considered. In the context of public health, to be able to follow trends in oral health and dental preventive behaviour of (young) adults, research monitoring oral health is of great importance.