In this paper, we have proposed a novel printed antenna with characteristics of miniaturization and triple-band, which is expected to be employed in Wireless Local Area Networks (WLAN) and Worldwide Interoperability for Microwave Access (WiMAX). Based on a conventional monopole antenna, the proposed antenna can operate in three different resonant modes by loading branches and slots into the antenna body. The antenna body is printed on the FR4 with relative permittivity of 4.4 and the dimension of only 24 mm × 19 mm × 1 mm, which is fed by CPW. With three distinct resonance modes, the impedance bandwidth of the designed antenna can fully cover three desired bands of WLAN (2.4～2.48 GHz), (5.55～5.825 GHz) and WiMAX (3.4～3.6 GHz). The antenna was designed and simulated by HFSS and a corresponding experimental prototype has been fabricated and tested. Good agreement between the simulation and measurement is obtained, and measured results also presents that the antenna has good omnidirectional radiation with peak realized gain of 3.8 dBi, which can meet the requirements of WLAN/WiMAX wireless application.