The present study deals with the study tea waste as an effective functional adsorbent for the removal of reactive blue 21(RB21) from aqueous solutions. The batch adsorption experiments were influenced by several parameters such as contact time, solution pH and mass of adsorbent and initial dye concentration. The results indicated that the maximum removal of RB21 dye by tea waste was after 90 minutes of contact time and at the nearly neutral pH of 6.0. Moreover, two isotherm models, namely Langmuir and Freundlich adsorption isotherm were used to describe the adsorption equilibrium of RB21 dye onto tea waste. The data obtained was in good agreement with Langmuir model than that of Freundlich model, showing a monolayer adsorption capacity of 28.99 mg/g. Furthermore, it was observed that tea waste did not require any supplementary pre-treatments; such as activation before the application. Collectively, this work highlights the promise of pristine TW, ability to harness it for adsorption of dyes, while also prioritizing areas for future research and development (e.g., collection of TW from local vendors and resulting in environmental friendly disposal of the same). The presented strategy exhibited excellent adsorption capacity of TW for the removal of RB21 from the aqueous solutions. Nonetheless, in most parts of the globe TW from local vendors is available without any cost, regeneration is not required and the saturated adsorbent can be disposed by incineration.