The potential use of banana (BP) and jackfruit peel (JFP) as eco-friendly and low-cost adsorbents for removal of brilliant green (BG) dye from waste water in the presence of ultrasonic field has been studied. Batch process has been used for adsorption kinetic, equilibrium, and thermodynamic studies. Results show that the amount of BG adsorbed and the rate of adsorption increased in presence of ultrasonic field. The adsorption of BG onto BP and JFP is fast (equilibrium time for the adsorption is about 25 min) and follows the pseudo-second-order kinetic model. The Langmuir isotherm shows the best fit for the adsorption of BG onto BP, where as both Langmuir and Freundlich adsorption isotherms show best fit for the adsorption of BG onto JFP (R-2=0.99). The maximum adsorption capacities calculated using the Langmuir isotherm are 21.74 and 31.25 mg/g at 313 K for BP and JFP, respectively. The Delta G values are negative at all operating temperatures, confirming that the adsorption of BG is spontaneous and thermodynamically favorable. The positive value of Delta S suggests the increased randomness at the adsorbate-adsorbent interface. Overall, our study suggests that BP and JFP can be used as an ecofriendly and low-cost agro-material for removal of BG dye from aqueous solutions.