There is a dearth of information in the literature regarding environmentally benign high-performance thin-layer chromatography (HPTLC) methods to determine tenoxicam (TNX). Therefore, designing and validating an HPTLC method to detect TNX in commercial tablets and capsules was the goal of this investigation. The green mobile phase utilized was the combination of ethanol/water/ammonia solution (50:45:5 v/v/v). The TNX was quantified at a wavelength of 375 nm. The proposed method's greenness profile was established using the Analytical GREEnness (AGREE) approach. The proposed methodology for determining TNX was linear in the range of 25−1400 ng/band. The proposed methodology for measuring TNX was accurate (% recoveries = 98.24−101.48), precise (% RSD = 0.87−1.02), robust (% RSD = 0.87−0.94), sensitive (LOD = 0.98 ng/band and LOQ = 2.94 ng/band), and environmentally friendly. The AGREE scale for the present methodology was derived to be 0.75, indicating an outstanding greenness profile. TNX was found to be highly stable under acidic, base, and thermal stress conditions. However, it completely decomposed under oxidative stress conditions. Commercial tablets and capsules were found to have 98.46 and 101.24% TNX, respectively. This finding supports the validity of the current methodology for measuring TNX in commercial formulations. The outcomes of this work showed that the proposed eco-friendly HPTLC methodology can be used for the routine analysis of TNX in commercial formulations.