The outlook for T-cell malignancies remain poor due to the lack of effective therapeutic options. Chimeric antigen receptor (CAR) immunotherapy has recently shown promise in clinical trials for B-cell malignancies, however, designing CARs for T-cell based disease remain a challenge due to the shared surface antigen pool between normal and malignant T-cells. Normal T-cells express CD5 but NK (natural killer) cells do not, positioning NK cells as attractive cytotoxicity cells for CD5CAR design. Additionally, CD5 is highly expressed in T-cell acute lymphoblastic leukemia (T-ALL) and peripheral T-cell lymphomas (PTCLs). Here, we report a robust anti-CD5 CAR (CD5CAR) transduced into a human NK cell line NK-92 that can undergo stable expansion ex vivo. We found that CD5CAR NK-92 cells possessed consistent, specific, and potent anti-tumor activity against a variety of T-cell leukemia and lymphoma cell lines as well as primary tumor cells. Furthermore, we were able to demonstrate significant inhibition and control of disease progression in xenograft mouse models of T-ALL. The data suggest that CAR redirected targeting for T-cell malignancies using NK cells may be a viable method for new and complementary therapeutic approaches that could improve the current outcome for patients.