T-cell acute lymphoblastic leukemia and T-cell lymphoblastic lymphoma are uncommon disorders classified together by the World Health Organization classification as "T-lymphoblastic leukemia/lymphoma." This review gives an overview on the treatment of these aggressive but curable T cell malignancies in adult patients, in order to highlight current developments. The most interesting and relevant developments are in our understanding of the genetics of T-ALL/LBL and how the genetics relate to clinical outcome. These studies will inform clinicians as to which targeted novel agents may be of value and how patients may be best risk-stratified to receive them.