• Pediatric subjects with JIA aged from 2 to less than 18 years who met entry criteria for the qualifying/index study and in the opinion of the investigator have sufficient evidence of JIA disease activity to warrant use of tofacitinib as a DMARD. Subjects turning 18 years of age during participation in the qualifying/index study or subsequently will be eligible for participation in this study.

• The subject has discontinued disallowed concomitant medications for the required time prior to the first dose of study drug, as defined in Appendix 1, and is taking only those concomitant medications in doses and frequency allowed by the protocol.

• Fertile male subjects and female subjects of childbearing potential who are, in the opinion of the investigator, sexually active and at risk for pregnancy with their partner(s) must be using a highly effective method of contraception as outlined in this protocol throughout the study and for at least 28 days after the last dose of study medication.

• Subjects must have previously completed participation in a qualifying study of tofacitinib for the treatment of JIA. Subjects who have required earlier discontinuation of treatment in a qualifying study for reasons other than tofacitinib related serious adverse events may be eligible.