In the present study, the nuclear factor-Y subunit B (GmNFYB1) gene, induced by abscisic acid (ABA), 8% polyethylene-glycol (PEG) 6000, and NaCl, was cloned from soybean. GmNFYB1 is located in the cell nucleus. Two independent transgenic Arabidopsis lines overexpressing GmNFYB1 and GmNFYB1-GR (GmNFYB1 fused with the glucocorticoid receptor) were generated to investigate the function of GmNFYB1 in abiotic stress tolerance. The GmNFYB1 lines exhibited a higher seed germination rate and longer root lengths, with increased proline accumulation in leaves and decreased water loss under drought and salt stress conditions. In contrast, the GmNFYB1-GR transgenic lines displayed almost the same growth pattern as the wild-type plants under ABA, salt, and drought treatments in the absence of dexamethasone (DEX). However, after DEX application as an inducer, the GmNFYB1-GR lines showed positive responses to drought and salt resistance, similar to the GmNFYB1 lines. The inhibition of seed germination under ABA stress indicates that GmNFYB1 is involved in the ABA signalling pathway. Furthermore, the quantitative reverse transcription real-time polymerase chain reaction (qRT-PCR) analysis suggested that GmNFYB1 boosts the stress tolerance of plants through the C-repeat binding factor pathway. Taken together, these findings demonstrate the characteristics of GmNFYB1 as a transcription factor that lead to improved drought and salt tolerance in plants.