The optical limiting (OL) properties of gold, silver and gold-silver alloy nanoparticles in methyl 2-methylprop-2-enoate are presented. The particles were generated by the technique of laser ablation and have hydrodynamic diameters from 26 nm to 30 nm. For the optical limiting measurements we used a Q-switched Nd:YAG laser working at a wavelength of 1064 nm or 532 nm, with a pulse width of 3 ns. The experimental results show that these nanoparticles have a strong nonlinear attenuation which can be attributed to intraband, interband and free-carrier absorption and that the surface plasmon resonance (SPR) does not contribute to the nonlinear processes at high input energies.