The new densities of binary mixtures of dimethyl sulfoxide (DMSO) with primary, secondary, and tertiary amines {2-aminoethanol (MEA), 2,2′-iminodiethanol (DEA), and bis(2-hydroxyethyl)methylamine (MDEA)} were measured at the atmospheric pressure for the temperatures ranging from (293.15 to 363.15)K over the entire composition range using an Anton Paar digital vibrating U-tube densimeter (model DMA 5000 M). A Redlich–Kister type equation was correlated using the excess molar volumes calculated with the experimental values and used to represent the densities of the liquid mixtures as a function of temperature and concentration. The thermal expansion coefficients of the pure components along with their binary mixtures using the experimental data are represented and discussed.