The present work aimed at studying the use of orange peel (OP) biosorption for the removal of methylene blue (MB) and Congo red (CR) from aqueous solution. The influences of initial dye concentration and contact time on the biosorption process were studied. Experimental data were modeled by Langmuir and Freundlich isotherms. The former fitted better the equilibrium data for both dyes. The monolayer biosorption capacity of OP was 256.4 and 102.0 mg/g for MB and CR, respectively. The calculated thermodynamic parameters, namely ∆G, ∆H and ∆S showed that the biosorption of the two dyes was spontaneous and exothermic under the examined conditions. Experimental data were also analyzed using biosorption kinetic models. The results showed that the biosorption processes of dyes on OP obey pseudo-second-order kinetics. Our results prove that an agriculture waste (i.e. OP) can be used to eliminate dyes from aquatic solution efficiently.