The intensity I of the ¹¹⁹Sn Mossbauer line in SnI₄ was measured from 100K to 300K at atmospheric pressure and at 200K at a pressure of 2 kbar. At low temperatures, the slope delta of lnI versus temperature is independent of temperature. Applying a Debye model with rigid motion of the SnI₄ molecules, one obtains an unusually low value of the Debye temperature ( theta =49K) which, however, is confirmed by ultrasonic measurements (57K). Above 170K, an increasing deviation from linearity of lnI versus temperature is observed. Furthermore, at higher pressure, a large increase of the Mossbauer intensity at 200K is observed. These two observations indicate that volume changes strongly influence the lattice dynamics. They are explained by a quasiharmonic model using a Gruneisen parameter equal to gamma =4+or-1.5.