In this paper, a novel multiple-input-multiple-output tri-band antenna with a featured embedded common mode (CM) choke is presented to prevent receiver desense and improve throughput for WLAN applications. The proposed antenna design consists of two wide-bandwidth high-efficiency electromagnetic structure elements with an Γ-shaped branch and an open-ended slot line in the element. The Γ-shaped branch is used to reduce the size of the antenna element. The open-ended slot line is a balun, which is used to reduce the CM current on the coaxial cable. The proposed antenna was simulated and measured, and the simulated results agree well with the measured ones. The results have also demonstrated that the proposed antenna is well suited for WLAN applications as it covers the three operating bands of 2.4G, 5.2G and 5.8G.