T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive malignancy caused by the accumulation of genomic lesions that affect the development of T-cells. Since many years, it has been established that deregulated expression of transcription factors, impairment of the CDKN2A/2B cell cycle regulators and hyperactive NOTCH1 signaling play prominent roles in the pathogenesis of this leukemia. In the past decade, systematic screening of T-ALL genomes by high resolution copy number arrays and next- generation sequencing technologies has revealed that T-cell progenitors accumulate additional mutations affecting JAK/STAT signaling, protein translation and epigenetic control, providing novel attractive targets for therapy. In this review, we provide an update on our knowledge on T-ALL pathogenesis, on the opportunities for the introduction of targeted therapy and on the challenges that are still ahead.