The third round of the International Self-Report Delinquency Study (ISRD3, 2012-2019) was a large international collaborative study of delinquency and victimization of 12- to 16-year-old students in seventh, eighth, and ninth grades. The ISRD3 data were collected in schools in online or paper and pencil mode. The standard design was a random cluster sample (primary sampling unit: classes) from schools from two major cities, with some countries collecting national level samples. The core aims included the description of crime rates and patterns, and the exploration of correlates of youth crime and youth victimization. For the study of correlates of youth crime involvement, theoretical sources ranged from situational action theory, institutional anomie theory, social and self-control theories to routine activities and social disorganization approaches. The ISRD3 sweep additionally incorporated a focus on police reporting rates, and a special module on police legitimacy based on procedural justice theory. The study was conducted in 35 countries from Europe, North and South America, Asia, and Africa. The Data Manual (file “ISRD3_Data-Manual.pdf”, available with the dataset) presents a short overview of the ISRD3 study, calls attention to important documents you will need when working with the ISRD3 dataset, presents general information about its variables, and gives general advice for using the data appropriately. It also contains a list of all contributors to this dataset.