SummaryAdoptive T‐cell therapy involves the ex vivo enrichment and expansion of tumor‐reactive T cells for infusion. As an immune‐based approach, adoptive therapy has become an increasingly attractive modality for the treatment of patients with cancer due to its potential for high specificity, non‐cross resistance with conventional therapies, and promise of long‐term immunoprotection. In recent years, a resurgence in discoveries underlying T‐cell recognition, tumor immune evasion, and T‐cell memory and differentiation coupled with the development of several enabling technologies have facilitated a renewed focus in the field of adoptive therapy and its transition to the clinical arena as a treatment modality for patients with cancer. In this review, endogenous T cells derived from peripheral blood or tumor sites will be presented as a source of effector cells for adoptive therapy and strategies to isolate, manipulate, and enhance the function of antigen‐specific T cells in vitro and to augment their in vivo efficacy and persistence by host immunomodulation are presented in the context of an ever‐increasing inventory of preclinical and clinically available reagents. Optimizing the combination of adoptive cellular therapy and other immune‐based and conventional approaches will herald a new generation of research and clinical opportunities for cancer immunotherapy.