Gold nanoparticles (AuNPs) are increasingly recognized for their potential in biology due to their excellent drug delivery capabilities and ease of synthesis. To create AuNPs using marine sponge Amphimedon compressa, we used several techniques, including ultraviolet-visible (UV-visible) spectrophotometry, Fourier transform infrared (FTIR) spectrophotometry, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and x-ray diffraction (XRD). The UV-visible spectroscopy results demonstrated the formation of stable AuNPs at a pH of 7, with a peak absorption at 564 nm. FTIR spectroscopy indicated that secondary metabolites featuring -OH functional groups acted as reducing agents in the production of AuNPs. Morphological analysis showed that the AuNPs were spherical, consistently shaped particles averaging 10-40 nm in diameter, with proven stability over time. The inhibition zones for the bacteria tested with the synthesized AuNPs varied from 26 to 31 mm. Both the AuNPs and the A. compressa extract displayed significant antioxidant activity, achieving DPPH radical scavenging percentages of 70.73% and 85.62%, respectively. In terms of anti-inflammatory activity, the AuNPs showed dose-dependent anti-inflammatory activity, with hemolytic inhibition percentages of 4.8%, 10.2%, 12.8%, 14.9%, 19.5%, and 22.4% at increasing concentrations. Furthermore, both the crude extract and the synthesized AuNPs exhibited adulticidal activity against the house fly (Musca domestica) and the mosquito (Culex pipiens). The LC and LC values for the crude extract were 34.988 and 62.836 ppm for M. domestica, and 9.258 and 17.399 ppm for C. pipiens. For the AuNPs, the corresponding values were 8.545 and 15.157 ppm for M. domestica, and 7.573 and 14.074 ppm for C. pipiens. Adult mortality caused by the AuNPs extract reached 100.00% for both Musca domestica and Culex pipiens at a concentration of 6 ppm. Overall, M. domestica and C. pipiens were more sensitive to AuNPs than to the crude extract. Both the synthesized AuNPs and the crude extract caused a significant, dose-dependent reduction in fecundity and hatchability in M. domestica and C. pipiens. In conclusion, the marine sponge A. compressa serves as an effective biological source for the synthesis of AuNPs, which demonstrate significant antibacterial, antioxidant, anti-inflammatory, anti-biofilm, and insecticidal activities, highlighting their potential in biomedical and environmental fields.