In the current framework of bioeconomy, there is growing interest in the use of renewable materials as raw materials to produce bioproducts. Glucose is recognised as a broad-spectrum starting material that can be obtained from carbohydrate-rich biomass. The controversy regarding the use of edible resources raises questions regarding its sustainability. The use of second-generation feedstocks, which are rich in lignocellulose, could be an attractive source of sugars. Currently, the processing of lignocellulosic materials is still in the research and development stages compared to the technologies used for processing edible feedstocks. However, the environmental analysis of different sugar productions can be carried out at this stage, since it is useful to evaluate the viability of the processes as they are conceived, as well as it is possible to identify those stages or units of the process on which efforts should focus in order to propose substantial improvements. This study aims to evaluate the environmental impact of sugars from crops (maize and sugar beet) and lignocellulosic biomass (maize stover), using the life cycle assessment (LCA) methodology. This study attempts to offer a wide vision of the evaluated processes and, for this purpose, 20 scenarios of sugar production were evaluated. Economic allocation was considered to distribute the impacts among the different by-products. Results show that, in terms of average values of the different scenarios, maize stover has a better environmental profile and contributes less to most of the environmental impacts compared to sugar beet and grain maize.