This work aimed to use raw soybean hulls (RSH) as an adsorbent on the removal of BF-4B reactive red dye. Kinetic and equilibrium experiments were performed using the best conditions obtained from preliminary tests. Kinetic data were better represented by the pseudo-second order model, evidencing three well-differentiated mass transfer regions. By a statistical analysis of the fit of 7 equilibrium models and 2 model combinations to experimental data, it was observed that the adsorption occurred in a single molecule monolayer for final dye concentrations lower than ~63 mg L−1. After this concentration, a possible multimolecular monolayer was verified, evidencing the formation of aggregates or micelles, since the Langmuir-BET model was the best fit. The maximum adsorption capacity estimated was about 19 mg g−1. The results have proved that the soybean hulls could be used as an alternative adsorbent in the treatment of textile effluents, without the need for a pretreatment.