In this study, we have reported precise high-temperature volumetric data of industrially important benzylamines, namely, benzylamine, N-methylbenzylamine, N,N-dimethylbenzyl-amine, and dibenzylamine. The effect of temperature and methyl or benzyl substitution on benzylamines have been discussed. Other physicochemical properties such as speed of sound, viscosity, and refractive index have been measured in the temperature range from 293.15 to 343.15 K and used to calculate several derived properties. Temperature dependence of density and refractive index data were fitted with the second order polynomial equation whereas viscosity data have been fitted well according to Arrhenius equation. The correlation between density and refractive index has also been quantified through a set of empirical equations. The molar refraction parameter has been estimated by Lorenz-Lorentz equation. Finally, the critical properties have been estimated with the modified Lydersen-Joback-Reid method and used to correlate the density of studied benzylamines.