Patients with mantle cell lymphoma (MCL) usually respond to initial combination chemotherapy, but the disease inevitably relapses and often follows an aggressive course. Here, clinical study results published since 2008 for patients with relapsed/refractory MCL were reviewed to compare available evidence for treatment guidance. Most trials identified were non-randomized, phase II studies performed at a limited number of sites, and many evaluated MCL as one of multiple non-Hodgkin lymphoma subtypes. Additional randomized, comparative trials are needed. Treatment selection generally depends on patient need, age and fitness, time of relapse, and line of therapy. Combination regimens typically produce higher response rates than single agents, and adding rituximab generally improves outcomes. The inclusion of ibrutinib, lenalidomide, temsirolimus, and bortezomib, represents an important advance for patients ineligible for, unable to tolerate, or failing high-intensity combination chemotherapy. A high need for effective treatments in relapsed/refractory MCL remains, particularly for elderly and frail patients.