Fano resonance is the degree of asymmetry that describes the interference of continuum states with discrete states and causes asymmetric line shape in the optical response. The hydrothermally synthesized TiO 2 nanostructures in this work are doped with 1.5 MeV carbon (C) ion beams to explore the Fano effect via the asymmetry in the Raman spectra. It is observed that the E g and A 1 g modes are asymmetric toward the lower wavenumber. The Fano effect is responsible for the peak asymmetry, which rises with C ion fluence. The Breit–Wigner–Fano line shape fits well the E g and A 1 g modes. The calculated asymmetry parameter (1/q) for implanted TiO 2 nanostructures represents weakly localized asymmetry with temperature. The electron–phonon coupling strength grows with the C ion fluence. The effects of temperature and defect level on the asymmetry parameter are also discussed.