OBJECTIVES:  Approximately 85% of patients with classical Hodgkin lymphoma (cHL) are cured with first-line therapy; half of those remaining can be cured with high-dose chemotherapy and autologous stem cell transplantation (ASCT). Less is known about outcomes among patients who have failed ASCT, particularly from real-world populations. The objective of this review was to estimate the proportion of patients with relapsed/refractory (RR) cHL, according to therapy after ASCT failure. METHODS:  A systematic review was conducted of observational studies from MEDLINE and EMBASE (2005–present). Two reviewers scanned all identified abstracts, reviewed full-texts, and extracted data from the final set of articles. RR cHL was reported as defined by the original investigators; patients may have also received other therapies post-ASCT. Study, patient, and treatment characteristics were tabulated, as were the n (%) of RR cHL according to therapy and mean follow-up from time of study enrollment. RESULTS:  From 8,096 identified abstracts, 110 full-texts were screened. A preliminary analysis was performed on 16 eligible articles (describing 15 studies), focusing on outcomes among post-ASCT patients treated with: brentuximab vedotin (BV; n=4 studies); BV followed by allogeneic-SCT (n=2); bendamustine (n=2); allogeneic-SCT (n=6); or various therapies (n=2). RR cHL was observed in 30% (at 38 weeks’ follow-up) to 62% (53 weeks) of patients treated with BV, 24% (104 weeks) to 38% (260 weeks) treated with BV followed by allogeneic-SCT, 26% (24 weeks) to 44% (48 weeks) treated with bendamustine, 40% (100 weeks) to 63% (100 weeks) treated with allogeneic-SCT, and 25% (100 weeks) to 39% (39 months) of patients treated with various therapies after ASCT. CONCLUSIONS:  Even with the availability of multiple therapies for advanced cHL, a substantial proportion of patients have RR disease. Our findings will help quantify the potential number of patients eligible for emerging therapies, estimates that will be useful for healthcare resource planning.