: This research aims to determine the effect of knowledge, attitude, school support, and facilities Occupational Safety and Health (OSH) to the application of K3. This research is quantitative research. A population of 716 and the sample amounted to 147 by proportional random sampling. Collecting data using tests, questionnaires and observations. Analysis of data using path analysis. The results showed: (1) knowledge of a significant effect on attitudes, (2) knowledge of a significant effect on the implementation of OSH, (3) OSH facilities significantly influence the implementation of OSH, and (4) the attitude significantly influence the implementation of OSH. Suggestion of this research, in order: (1) schools improve policy, funding, and resources, (2) teachers improve the learning process, and (3) students have a sense of responsibility towards the equipment OSH