Edible oil adulteration is a significant food safety issue that compromises nutritional quality, product authenticity, and consumer health. This study investigated the quality of ten commercially and locally available edible oils using a combination of physicochemical analysis and gas chromatography–mass spectrometry (GC–MS). Free fatty acid content, acid value, moisture content, relative density, refractive index, and saponification value were determined and compared with standard reference ranges. Several samples, particularly local refined, peanut, yellow-seed, olive, and sunflower oils, exhibited values exceeding acceptable limits, indicating possible adulteration or quality deterioration. GC–MS analysis of commercial mustard and refined oils identified their characteristic fatty acid profiles while also detecting glycidyl palmitate, a processing-related contaminant, and linoleyl palmitate, suggesting compositional alterations. The findings demonstrate that integrating routine physicochemical testing with GC–MS provides a reliable and effective approach for detecting adulteration, assessing edible oil quality, and supporting food safety surveillance and regulatory quality control.