Byproducts of simultaneous saccharification and fermentation (SSF) from sugarcane bagasse using steam explosion (SE, 190 °C for 10 min and 210 °C for 5 min) and green liquor (GL) combined with hydrogen peroxide (GL–H₂O₂) or ethanol (GL–ethanol) pretreatments were compared. Results showed that SE pretreatments did not result in lactic acid because a majority of the glucose was consumed for yeast growth and ethanol production, and the ethanol yield of 93.86% (of the theoretical) at 190 °C for 10 min and 94.33% at 210 °C for 5 min were achieved. Most of the hemicelluloses were removed and more acetyl groups were generated after the SE pretreatment, so it always had the highest amount of acetic acid (1.22 g L⁻¹ at 190 °C for 10 min and 1.38 g L⁻¹ at 210 °C for 5 min). GL–ethanol pretreatment resulted in an ethanol yield of 80.56%. However, the existence of reactive lignin from organic solvent produced high amount of byproducts, especially for the maximum glycerol contents (0.818 g L⁻¹). Deficient lignin removal and sugar degradation with GL–H₂O₂ pretreatment led to the lowest ethanol yield of 23.23%, which may be because some inhibitors generated from GL–H₂O₂ pretreatment affected hydrolysis efficiency and yeast activity in the SSF process.