<p>This study investigates the synthesis and characterization of pure and surfactant-assisted tin oxide (SnO₂) nanoparticles (NPs) to improve their wettability and optical properties due to morphological changes. Surfactants, including the sodium dodecyl sulphate (SDS—anionic), cetyltrimethylammonium bromide (CTAB—cationic), and polyvinylpyrrolidone (PVP—capping agent), were used for the synthesis of SnO₂ NPs using the hydrothermal method to investigate their influence on particle size, surface morphology, and functionality. Structural and morphological investigations using XRD, FTIR, Raman, and SEM revealed significant changes in crystallite size and surface morphology resulting from surfactant-assisted growth mechanisms. The BET analysis demonstrated a significant variation in surface area and porosity. Water contact angle measurements suggested an improved wettability in surfactant-assisted samples, particularly for SDS. Moreover, UV–Vis spectroscopy and photoluminescence investigations confirm enhanced optical absorption and emission characteristics with SDS-assisted tin oxide NPs showing the highest optical band gap of 3.68&#xa0;eV due to morphology-induced quantum confinement effects. The results highlight a substantial relationship between surfactant type, nanoparticle morphology, and the resulting functional properties. This work presents a systematic comparison of hydrothermally synthesized anionic (SDS), cationic (CTAB), and polymeric (PVP) capping agents assisted tin oxide nanoparticles, as well as a quantitative correlation between surfactants and morphology, surface area, wettability, and optical properties of tin oxide nanoparticles.</p> Graphical abstract <p></p>