BACKGROUND: The GATA transcription factors play multifaceted roles in modulating vital physiological processes in plants. However, the GATA transcription factor family in onion (Allium cepa L.) has been explored to a limited extent. In the present study, a genome-wide survey of the GATA family and the subsequent characterization has been carried out in the onion genome. RESULTS: In total, 24 A. cepa GATAs (AcGATA1-AcGATA24) have been identified in the onion genome. Chromosomal mapping revealed that all identified genes could be mapped onto different onion chromosomes or scaffolds. The gene duplication, synteny, and collinearity analysis of the AcGATAs suggested their divergence, expansion, and selection in onions. Phylogenetic analysis of the AcGATAs divided them into five groups along with other plant GATAs. Gene ontology and cis-regulatory element analysis results suggested that the AcGATAs could regulate crucial processes, such as growth and development, phytohormone signalling, and stress response. The tissue-specific expression study indicated that the AcGATAs expressed in multiple onion tissues. The expression analysis under subjected chromium and salt stress revealed that multiple AcGATAs get induced in response to the applied stresses. Lastly, the protein interaction network study predicted some key interacting partners of the AcGATAs that can regulate vital physiological processes in onions. CONCLUSIONS: The present study identified and characterized the GATA gene family in onions. Functional predictions and interaction network analysis suggested the roles of AcGATAs in modulating multiple onion physiological processes. The induced expression of AcGATAs under chromium and salt stress indicated their involvement in abiotic stress response in onions. Overall, the study provides newer insights into the GATA gene family and their possible roles in onions.