This study explores the development of an eco-friendly, cost-effective surfactant derived from Neem seed oil, aimed at reducing production costs and environmental impact in pharmaceutical and cosmetic applications. Surfactants, which reduce surface and interfacial tension, are crucial across industries, including pharmaceuticals, but the high cost and non-biodegradability of synthetic surfactants pose economic and environmental challenges. Neem oil was extracted via Soxhlet extraction with hexane, then sulphonated to produce Neem Sulphonated Oil (NSO), an amphiphilic surfactant with both hydrophilic and hydrophobic groups. The NSO was characterized using Fourier Transform Infrared (FTIR) spectroscopy, revealing successful sulfonic acid incorporation, and its physiochemical properties—including specific gravity, acid value, and saponification value—were analyzed. Results showed the NSO's specific gravity at 2.68 gcm⁻3, a saponification value of 161 mg KOH g⁻1, and acid value of 97.6, with high water solubility. In stability tests, emulsions containing NSO (2–12% w/v) showed prolonged creaming time compared to sodium lauryl sulfate (SLS), a commonly used synthetic surfactant. Further stability enhancement was observed when NSO was combined with acacia gum. The findings suggest that Neem oil, being abundant, biodegradable, and non-toxic, holds promise as a renewable surfactant source for pharmaceutical emulsions. This study is unique in focusing on Neem oil’s applicability in the pharmaceutical and cosmetics sectors, offering a natural alternative to synthetic surfactants that may reduce importation costs and environmental impact. Future research should assess the Neem oil-derived surfactant’s fatty acid composition, surface tension, hydrophilic-lipophilic balance (HLB), and critical micelle concentration (CMC) to further validate its potential for industrial applications in Nigeria and beyond.