SummaryA low‐profile, tri‐band, wide slot antenna for the Wireless Local Area Network (WLAN) and World‐Wide Interoperability for Microwave Access (WiMAX) applications is proposed in this article. The surface dimension of the proposed planar antenna is 0.32λ × 0.32λ mm2 (lowest operating frequency). The antenna structure consists of a wide slot which is formed by carefully etching out the square and circular shapes from the basic patch antenna. The standard cost‐effective FR‐4 substrate with a thickness of 1.6 mm is used for the fabrication of the prototype. Tri‐band resonance at 2.4, 3.5, and 5.5 GHz is achieved with the peak gain of 3.33, 1.12, and 1.37 dBi, respectively. The impedance bandwidth at three resonant peaks is 15.36%, 11.7%, and 8.29% with Voltage Standing Wave Ratio (VSWR) well below the requirement of 1.5. Dipole‐shaped radiation patterns, average gain > 1.96 dBi, and efficiency of 83% make the antenna commercially viable for use in WLAN and WiMAX devices.