In Malaysia, water pollution due to the various heavy metal contaminants has become a serious issue that needs to be concerned. Among various water treatment methods, the adsorption method has been considered one of the most efficient wastewater treatment techniques. This study was done to find out the adsorption capacity of orange peel (OP) by different pre-treatment in removing copper, chromium, and nickel ion from aqueous. OP powder was divided into three portions, which were untreated OP, pretreated with sodium hydroxide (NaOH) OP, and detergent OP respectively. Each chemical solution that contains copper, chromium and nickel respectively was tested by these three adsorbents. From the experiment, NaOH pretreated OP was found highest performance in removing 85.67% of nickel and 81.55% of copper. While the untreated OP was good in removing 91.2% of chromium. The untreated OP for nickel ions and copper ions, Detergent treated OP for nickel ions and chromium ions were best fitted to Langmuir Isotherm, while untreated OP for chromium ions, detergent treated OP for copper ions and NaOH treated OP for all selected metal ions were best fitted to Freundlich Isotherm. In short, OP can be considered a very good adsorbent choice due to its good adsorption capacity, environment-friendly nature and low-cost characteristics.