Lignocellulosic agricultural residues are abundant, underused feedstocks whose open burning contributes to environmental pollution. This study evaluated sugarcane bagasse, wheat straw, and corn cob for integrated xylitol and ethanol production. Biomass was subjected to acid or alkali pretreatment followed by enzymatic saccharification, and the resulting liquor and residual fractions were fermented with Kluyveromyces spp. and Saccharomyces cerevisiae. Alkali–enzyme-treated sugarcane bagasse liquor produced the highest xylose concentration (36.27 g/L), whereas its residue contained 6.21 g/L glucose. Kluyveromyces spp. produced 28.54 g/L xylitol from sugarcane bagasse liquor, corresponding to a reported yield of 78.68% and volumetric productivity of 0.016 g/L/h. S. cerevisiae produced 4.26 g/L ethanol from the bagasse residue, with a reported yield of 69.40% and productivity of 0.236 g/L/h. Wheat straw hydrolysate showed the highest reported apparent xylitol yield (121.29%) at pH 6, indicating a need to verify the yield basis while confirming the strong influence of substrate composition and pH. Overall, combining alkali pretreatment with enzymatic saccharification improved fermentable-sugar recovery and supported dual-product valorization of agricultural residues. Sugarcane bagasse was the most promising feedstock for integrated xylitol and ethanol production, although scale-up, inhibitor control, and techno-economic evaluation remain necessary.