Endometriosis affects a significant proportion of teenagers. Published studies suggest that laparoscopically confirmed endometriosis could be found in over 60% of adolescent girls undergoing laparoscopic investigation for pain, in 75% of girls with chronic pelvic pain resistant to treatment and in 70% of girls with dysmenorrhea and in approximately 50% of girls with chronic pelvic pain not necessarily resistant to treatment. Both early and advanced forms, including deep endometriosis have been reported to be present in teenagers. It has recently been claimed that deep endometriosis has its roots in teenage years. Risk factors include obstructive mullerian anomalies, family history, early menarche and early onset dysmenorrhea. Both surgical and medical treatment approaches are used for treatment in this age group, but care should be taken when treatment with GnRHa and progestins is being considered due to their potential impact on bone formation. Further studies are urgently needed to determine whether early diagnosis and treatment of teenage endometriosis lead to better long term outcomes or simply increase number of interventions without preventing progression of the disease.