The GATA family is a group of zinc finger transcription factors that plays important roles in regulating developmental processes. However, the functions of GATA family members in the response of plants to drought and salt stress remain poorly studied. Here, we isolated a novel GATA gene (IbGATA24) from sweetpotato. The expression of IbGATA24 was strongly induced by PEG6000, NaCl, and abscisic acid (ABA) treatments. IbGATA24 was located in the nucleus and exhibited no transactivation activity. IbGATA24-overexpressing plants showed significantly enhanced tolerance to drought and salt stress. The leaf water loss rate and the leaf stomatal aperture of overexpression plants were significantly decreased. Genes involved in abscisic acid and jasmonic acid signaling pathways, and reactive oxygen species scavenging were up-regulated in transgenic plants under drought and salt treatments. The ABA, JA, and proline content and the activity of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) were significantly higher, and the accumulation of malondialdehyde (MDA) and H₂O₂ was lower, in transgenic plants than in wild-type plants under stress conditions. IbGATA24 could interact with constitutive photomorphogenesis 9-5a (COP9-5a). Overexpression of IbCOP9-5a enhanced drought and salt stress resistance through regulating ABA and reactive oxygen species (ROS) accumulating. These results suggest that IbGATA24 interacting with IbCOP9-5a plays a positive regulatory role in abiotic stress tolerance. Our study identified a novel GATA transcription factor that could be used to improve the tolerance of sweetpotato and other plants to abiotic stress.