Soybean yield is mainly influenced by the interaction among genotype, environmental conditions and management practices. Based on that, the aim of this study was to quantify the soybean yield gap caused by water deficit (YGWD) and sub-optimum crop management (YGCM), considering data from the areas of soybean yield contest in Brazil. Potential (Yp) and attainable (Ya) yields were estimated by a crop yield simulation model, whereas actual farmers yields (Yf) were obtained from the contests conducted by the Brazilian Soybean Strategic Committee (CESB), comprising 200 sites. The YGWD and YGCM were, respectively, calculated by the difference between Yp and Ya, and Ya and Yf. The climate efficiency (EFC) was obtained by the ratio between Ya and Yp, while crop management efficiency (EFM) considered the ratio between Yf and Ya. The mean Yf from CESB was 5021 kg ha−1, higher than the national average of about 3000 kg/ha.