Soybean [Glycine max (L.) Merr.] provides oil and protein for fuel, food, and feed around the world. The limited genetic diversity of domesticated soybean threatens future yield and limits breeders’ ability to optimize the nutrient composition of soybean. Glycine soja (L.) Merr. is a wild relative of soybean that is substantially more genetically and phenotypically diverse than domesticated soybean. Breeding advances have overcome many of the challenges of breeding with G. soja. Genomics and publicly available marker data facilitated the identification of a genetically diverse core set from the USDA G. soja germplasm collection and allowed the identification of progeny that capture the valuable genetic diversity present in the wild germplasm. Valuable seed composition traits have been identified among wild soybean accessions. We extend these observations to include the seed ionome of 84 wild soybean accessions. Measurement of the concentrations of 19 elements from wild soybean seeds and 13 G. max accessions from multiple environments show that 17 of the element levels have a range of heritabilities and are substantially influenced by the environment. The average concentrations of many elements were higher in the wild soybean than domesticated soybean and also varied among maturity groups. Genetic markers potentially associated with improved mineral composition of Glycine seed have also been identified. This variation may be sufficient to improve mineral content of soy meal. Notably, S concentrations were higher in G. soja, and S levels correlate with total protein levels and S-containing amino acids. These observations may be used by breeders to improve seed composition of soybean.