In the present study, TiO₂ nanoparticles (NPs) were green-synthesized for first time using the extracts of Azadirachta indica twigs, Ficus benghalensis and Syzygium aromaticum. The green-synthesized G-TiO₂ NPs were widely characterized by UV-Vis spectroscopy, XRD, FTIR, DRS-UV, HR-TEM, EDX and Zeta potential. The shapes of the G-TiO₂ NPs are crystalline and tetragonal. The antibacterial and antibiofilm activities of G-TiO₂ NPs were tested against bacteria (Streptococcus mutans and Citrobacter freundii) and fungi (Candida albicans). Both the bacterial and fungal biofilms were inhibited at 100 μg mL⁻¹. Furthermore, the mosquito larvicidal activity was evaluated against the Zika virus vector Aedes aegypti. The mortality of A. aegypti was 98% at 75 μg mL⁻¹ of G-TiO₂ NPs. The LC₅₀ and LC₉₀ values were 12.2 and 61.21 μg mL^-1, respectively. Additionally, the photocatalytic activity of G-TiO₂ NPs was determined by the degradation of organic dye (methylene blue) and the pharmaceutical drug (paracetamol). The photocatalytic degradation efficacy of G-TiO₂ NPs was greater against paracetamol (88%) compared to the methylene blue (70%).