<p>A critical strategy for the viability and sustainability of lignocellulosic crops is the inclusion of high-value bioproducts in a biorefinery’s portfolio. In this context, the production of xylooligosaccharides (XOS) from the underutilized hemicellulose fraction of biomass is an interesting option for the valorization of the sugarcane bagasse. In this work, a life cycle assessment (LCA) of XOS production annexed to an existing sugar mill with self-sufficient energy supply was performed, aiming to determine the feasibility of the integration of XOS production in sugarcane biorefineries considering the scarcity of environmental studies of this value-added product. Furthermore, the impact of various energy sources on environmental indexes was assessed. The LCA scope was set as cradle-to-gate using 1&#xa0;kg of XOS as functional unit according to the standardized ISO procedure considering CML Baseline method. The plant was able to produce 4.19&#xa0;kg/h of 90.3% (w/w) XOS from 0.7 t/h of sugarcane bagasse with global warming potential (GWP) estimated as 6.31 kgCO_2eq/kg_XOS. The biomass hydrolysis and pretreatment stages were responsible for most part of the environmental footprint due to the chemicals and utilities necessary. Sensitivity analyses showed that energy-related variables had the greatest impact on environmental performance, accounting for a significant proportion of environmental impacts in almost all categories. Comparing with other valuable molecules, XOS was found to be an important alternative for the valorization of the underutilized hemicellulose fraction of the lignocellulosic material. Overall, the use of XOS in the sugarcane biorefinery and the integration of energy in the process were found to be crucial for the sustainability of the process and valorization of the sugarcane bagasse with the integration of energy into the XOS production process as key factor in improving its sustainability and productivity.</p>