A novel CPW-fed antenna capable of triple-band operation for WLAN/WiMAX applications is presented and investigated in this paper. The proposed antenna simply consists of three elements viz. folded open stub, L-shaped open stub, and Y-shaped resonator. By using the three elements, triple-band antenna operating at 2.5/3.5/5.5 GHz can be achieved. The antenna impedance bandwidths for |S11| ≤ −10 dB are 2.39–2.69, 3.38–3.73 and 5.0–5.99 GHz, covering all the WLAN/WiMAX operation bands. The tri-band antenna has good omnidirectional radiation patterns in H-plane and moderate gains across all the operation bands with compact size of 30 × 18mm2. Experimental results show that the antenna is successfully simulated and measured, and the tri-band antenna can be achieved by adjusting the lengths of the three elements and gives good gains across all the operation bands.