We present a method to determine the thermal boundary conductance of gold nanoparticles in aqueous solution. The novel approach consists of two steps: first, measuring photoacoustic signals originated by laser-induced nanobubbles at different energies and, second, fitting the experimental data with a nanobubble generation model developed in a previous work. We used this method on gold nanoparticles with diameters from 10 to 70 nm. Within this range, we obtained values of the thermal boundary conductance between 180 W/m2 K and 225 W/m2 K.