Plasmon resonance tuning was performed by femtosecond laser processing of silver-contained TiO₂ sol–gel films. We consider the key role of utilized wavelengths −343 nm and 515 nm, in terms of changing morphology, nanoparticles size and spectrum. The plasmon resonance peak of processed films exhibits an overall decrease (from 2.8 to 2.5 eV) with the increasing of laser fluence in the case of 515 nm. The 343 nm wavelength demonstrates a constant position of the plasmon resonance peak with a higher intensity and narrower half-breadth, which are explained by the difference of photo-thermal mechanisms activated.