Acoustic and optical Debye temperatures are calculated and correlated for rare earth tellurite glass systems. The binary tellurite vitreous systems can be represented by the general formula [TeO2]0.9 [AnOm]0.1, (A ‐ La, Ce, and Sm). The acoustic Debye temperature data are obtained from ultrasonic velocity (longitudinal and shear) measurements. The optical Debye temperatures are calculated from infrared absorption spectra. The Debye temperature ΘD derived in this way characterizes the total vibrational spectrum in that optical and acoustic modes are separated.