Background: Schizophrenia is categorized as an acute mental illness with specific criteria in a form of delusions, hallucinations, perception, difficulties in thinking, difficulties in accepting realities, unstable emotion, difficulties in behavior and difficulties in building interpersonal relation. Schizophrenia patient will undergo social function alteration so that he will find difficulties to fulfill his social function. Social skill training is a therapy referring to the social principals to increase communication and social skill for people with difficulties in interacting so that they are able to fulfill their social function. This research is needed to find out the influence of social skill training to the social function of schizophrenia patients. Method: This research was a quasi-experimental research with pretest-posttest with one group design. The sampling technique used was purposive sampling. There was 29 samples with intervention group. The intervention was conducted 6 times at Puskesmas (Community Health Service) Temon I, Tempel, Srandakan and Playen II in Yogyakarta during December 2016 until April 2017. Result: The analysis result form Wicoxon was p=0,000. Conclusion: Since p<0.05, it could be concluded that the social skill training was influential to the social function of people with schizophrenia