This article deal with study of the vibration spectra of hydroxyl ions and radiation-induced molecular complexes with H-bond in LiF:OH crystals. The IR spectra of the crystals were measured at 300, 80 and 10 K temperatures. The low-temperature behavior of the bands in the 3570–3700 cm−1 region indicates that corresponding vibration energy levels are not associated with phonons. It is shown that the broadening of 3730 cm−1 band with increasing temperature due to phonon interactions, namely, resonant scattering of phonons by vibrations of free hydroxyl. The frequencies of the transverse and longitudinal optical modes of phonons take part in the Fermi resonance splitting of the absorption band of molecular complexes with a strong hydrogen bond in the region of 1800–2300 cm−1 in LiF:Mg, OH crystals. It is determined that the narrow bands in the 3400–3700 cm−1 region can appear in the spectrum of LiF:OH without magnesium ions. It was concluded that narrow bands in the 3400–3700 cm−1 region in y-irradiated to a dose of 2.58×104 C/kg at T = 525 K LiF:OH crystals are caused by an associates of two or more hydroxyl ions or by a complexes with a hydrogen bond OH…O or OH…F.