A compact triple-band inverted-F antenna for WLAN and WiMAX multiple-input- multiple-output (MIMO) system is proposed in the paper. Its main radiation element is evolved from simple inverted-F antenna, works at 2.4 GHz, 3.5 GHz. The parasitic element works at 5.2 GHz, 5.8 GHz, In order to reduce the size of the antenna and improve the effect of the truncated ground plane on impedence match, a slot is added. A four-element array configuration of the proposed antenna for MIMO application is also studied. The siumulation results of reflection coefficient, mutual coupling, and radiation pattern are presented.