In this paper, an ultra-miniaturized triple-band antenna based on an epsilon negative transmission line (ENG-TL) approach is presented. The proposed antenna has a miniaturized electrical size of 0.247λ0×0.185λ0×0.019λ0 at 3.71 GHz which has been achieved by means of zeroth-order resonance (ZOR). This is recognized as an attractive technique to achieve compactness. It is observed from measured results that the proposed antenna is performing well over 3.63–3.81, 5.21–5.33, and 6.79–7.09 GHz. The novelty of this work lies in the fact that the peak gain has been improved by 1.73 dBi at the lowest order resonant mode. The antenna is able to exhibit measured peak gain of 1.97, 1.09, and 3.42 dBi in the broadside direction at 3.72, 5.27, and 6.92 GHz, respectively. Hence proposed antenna is suitable to work for Wi-MAX 3.5 GHz (3.4–3.8 GHz), WLAN/Wi-Fi 5.2 GHz (5.15–5.35 GHz), mobile/satellite (E-S) (6.875–7.075 GHz) applications.