A systematic study of the Raman spectra of the titanomagnetite solid-solution series (Fe3–xTixO4) for x = ~0.0, 0.2, 0.4, and 0.6 has been conducted. The samples showed combinations of five previously predicted Raman peaks at ~190, 310, 460, 540, and 670 cm−1 that correspond to vibrational modes with T2g(1), Eg, T2g(3), T2g(2), and A1g, respectively. The calibration of Raman spectra for titanomagnetite with known values of Ti concentrations reveals a strong dependence of relative intensity for the T2g(2) and T2g(3) modes on Ti concentration. The most prominent feature is the appearance and increase in the relative intensity of a T2g(3) peak above x = ~0.2. On the other hand, the Raman peak for the T2g(2) mode gradually diminishes as Ti increases and nearly disappears at x = ~0.6. Combining the two relative intensities potentially provides a sensitive indicator of Ti content. The technique was applied to study titanomagnetite in grains from Hana Volcanics and melatroctolite from Rhode Island.