RNA interference has tremendous yet unrealized potential to treat a wide range of illnesses. Innovative solutions are needed to protect and selectively deliver small interfering RNA (siRNA) cargo to and within a target cell to fully exploit siRNA as a therapeutic tool in vivo. Herein, we describe ammonium-functionalized carbon nanotube (fCNT)–mediated transport of siRNA selectively and with high efficiency to renal proximal tubule cells in animal models of acute kidney injury (AKI). fCNT enhanced siRNA delivery to tubule cells compared to siRNA alone and effectively knocked down the expression of several target genes, including Trp53, Mep1b, Ctr1, and EGFP. A clinically relevant cisplatin-induced murine model of AKI was used to evaluate the therapeutic potential of fCNT-targeted siRNA to effectively halt the pathogenesis of renal injury. Prophylactic treatment with a combination of fCNT/siMep1b and fCNT/siTrp53 significantly improved progression-free survival compared to controls via a mechanism that required concurrent reduction of meprin-1β and p53 expression. The fCNT/siRNA was well tolerated, and no toxicological consequences were observed in murine models. Toward clinical application of this platform, fCNTs were evaluated for the first time in nonhuman primates. The rapid and kidney-specific pharmacokinetic profile of fCNT in primates was comparable to what was observed in mice and suggests that this approach is amenable for use in humans. The nanocarbon-mediated delivery of siRNA provides a therapeutic means for the prevention of AKI to safely overcome the persistent barrier of nephrotoxicity during medical intervention.