Herein, the methylene blue (MB) biosorption from the agroindustrial residue (cassava bagasse) is reported. The cassava bagasse residue presented an irregular surface, anionic character, and low specific surface area. The experiments were performed in batch mode. The biosorption behavior was investigated through the experimental variables, initial concentration of MB, pH, and temperature. The maximum biosorption capacity (170.13 mg g −1 ) reached 328 K and pH 10.0. The equilibrium and kinetics were better fitted by the Sips and general order (R 2 ≥ 0.997 and R 2 adj ≥ 0.996) models, respectively. Furthermore, the thermodynamic study revealed a spontaneous (ΔG 0 < 0) and endothermic process. Finally, the results showed cassava bagasse is a potential material for biosorption dyes from the aqueous medium. In addition, the biosorbent has a low aggregate cost and high availability, which contributes to the destination of large amounts of waste and inspires engineering applications.