Relapsed/refractory T-cell acute lymphoblastic leukemia (T-ALL) has a dismal outcome, and no effective targeted immunotherapies for T-ALL exist. The extension of chimeric antigen receptor T-cells (CARTs) to T-ALL remains challenging because the shared expression of target antigens between CARTs and T-ALL blasts leads to CARTs fratricide. CD1a is exclusively expressed in cortical T-ALLs, a major subset of T-ALL. The expression of CD1a is restricted to cortical thymocytes and neither CD34+ progenitors nor T-cells express CD1a during ontogeny, confining the risk of on-target/off-tumor toxicity. The present invention provides CARs comprising a CD1a-targeting moiety which may be transduced or transformed into T cells. The resultant CARTs are suitable for the treatment of cortical T-ALLS.