The conformational stability of 2-(methylthio)ethanol has been studied by matrix-isolation infrared spectroscopy and ab initio MO calculations. In an argon matrix, the conformer with gauche-gauche-gauche’ (GGg’) around the CS-C-C-OH bonds is the most stable and the G’Gg’ conformer is the second most stable. These and the TGg’ conformers are stabilized by intramolecular hydrogen bonding between the hydroxyl hydrogen atom and the sulfur atom. The relative strength of the hydrogen bonding in these conformers is in the order GGg’ > TGg’ > G’Gg’, as estimated from the nonbonded OH ... S distance. In the G’Gg’ conformer, an additional intramolecular interaction between the methyl hydrogen atom and the hydroxyl oxygen atom is involved. The relative strength of this 1,5-CH ... O interaction in the G’Gg’ conformer is the least among the three relevant conformers with G’G around the CS-C-COH bonds. The calculated results indicate that the geometry of this conformational form is considerably distorted so that it is simultaneously accessible to both of the interactions. This geometry is, however, not best suited for the respective interactions to be the most effective. The results for 2-(methylthio)ethanol have been compared with those for 2-methoxyethanol, in which the analogous intramolecular interactions are involved. The present study emphasizes the importance of the intramolecular interactions in the conformational stabilization of 2-(methylthio)ethanol and other relevant compounds.