Soybean (Glycine max [L.] Merr.) is a major oil-producing crop worldwide. Although several related proteins regulating soybean oil accumulation have been reported, little is known about the regulatory mechanisms. In this study, we characterized vascular plant one-zinc-finger 1A (GmVOZ1A) that interacts with WRINKLED 1a (GmWRI1a) using yeast 2-hybrid library screening. The GmVOZ1A-GmWRI1a interaction was further verified by protein-protein interaction assays in vivo and in vitro. GmVOZ1A enhanced the seed fatty acid and oil contents by regulating genes involved in lipid biosynthesis. Conversely, a loss-of-function mutation in GmVOZ1A resulted in a reduction in triacylglycerol (TAG) content in soybean. Protein-DNA interaction assays revealed that GmVOZ1A and GmWRI1a cooperate to upregulate the expression level of acyl-coenzyme A-binding protein 6a (GmACBP6a) and promote the accumulation of TAG. In addition, GmACBP6a overexpression promoted seed fatty acid and oil contents, as well as increased seed size and 100-seed weight. Taken together, these findings indicate that the transcription factor GmVOZ1A regulates soybean oil synthesis and cooperates with GmWRI1a to upregulate GmACBP6a expression and oil biosynthesis in soybean. The results lay a foundation for a comprehensive understanding of the regulatory mechanisms underlying soybean oil biosynthesis and will contribute to improving soybean oil production through molecular breeding approaches.