The far infrared spectrum from 370 to 50cm−1 of gaseous 2-bromoethanol, BrCH2CH2OH, was recorded at a resolution of 0.10cm−1. The fundamental O–H torsion of the more stable gauche (Gg′) conformer, where the capital G refers to internal rotation around the C–C bond and the lower case g to the internal rotation around the C–O bond, was observed as a series of Q-branch transitions beginning at 340cm−1. The corresponding O–H torsional modes were observed for two of the other high energy conformers, Tg (285cm−1) and Tt (234cm−1). The heavy atom asymmetric torsion (rotation around C–C bond) for the Gg′ conformer has been observed at 140cm−1. Variable temperature (−63 to −100°C) studies of the infrared spectra (4000–400cm−1) of the sample dissolved in liquid xenon have been recorded. From these data the enthalpy differences have been determined to be 411±40cm−1 (4.92±0.48kJ/mol) for the Gg′/Tt and 315±40cm−1 (3.76±0.48kJ/mol) for the Gg′/Tg, with the Gg′ conformer the most stable form. Additionally, the infrared spectrum of the gas, and Raman spectrum of the liquid phase are reported. The structural parameters, conformational stabilities, barriers to internal rotation and fundamental frequencies have been obtained from ab initio calculations utilizing different basis sets at the restricted Hartree–Fock or with full electron correlation by the perturbation method to second order. The theoretical results are compared to the experimental results when appropriate. Combining the ab initio calculations with the microwave rotational constants, r0 adjusted parameters have been obtained for the three 2-haloethanols (F, Cl and Br) for the Gg′ conformers.