The adsorption capacity of activated carbon obtained from Thevetia peruviana for three basic dyes, namely Malachite Green, Crystal Violet and Rhodamine B, available in synthetic textile effluents has been studied. The percentage removal of Malachite Green, Crystal Violet, and Rhodamine B on to the activated carbon decreases from 98.46 to 89.80, from 97.83 to 88.66 and from 97.33 to 87.12 respectively with the increase in initial dye concentration from 25 mg/L to 100 mg/L at 30 degrees C. The removal data have been analyzed using Langmuir, Freundlich, Temkin and D-R isotherm models at various temperatures varying from 30 degrees C to 45 degrees C. The positive value of enthalpy indicates that the adsorption of basic dyes on to activated carbon is endothermic, which is further supported by the increase in adsorption rate of dyes with the increase in temperature from 30 degrees C to 45 degrees C. It is found that an activated carbon prepared by the chemical impregnation of Thevetia peruviana with H3PO4 acid can be used as the best adsorbent for the removal of basic dyes from synthetic textile effluents.