Peripheral T-cell lymphomas (PTCLs) are malignancies of immunologically mature T-cells that arise in peripheral lymphoid tissues such as lymph nodes, spleen, gastrointestinal tract, and skin. These lymphomas are uncommon as compared with the incidence of B-cell lymphomas, and they comprise only 5% to 10% of non-Hodgkin lymphomas in North America and Western Europe. A variety of specific disease entities have been recognized among PTCLs, and they tend to have lymph node, extranodal/cutaneous, or mixed leukemic/lymphomatous presentations. Most PTCLs have an aggressive clinical course. The clinicopathologic features of the various PTCLs are described herein.