This paper presents the buckling and vibration behavior of a viscoelastic sandwich cylinder in a thermal environment analyzed using the semi analytical finite element method. The analysis is carried out using a decoupled thermo mechanical formulation. The temperature field in the shell domain is evaluated using an eight-noded axisymmetric ring element. Buckling and vibration analyses are carried out using a two-noded sandwich shell element in the semi-analytical finite element method. Buckling temperatures are calculated for sandwich shells with two different core materials. The effect of temperature-dependent core shear modulus on buckling temperature and vibration behavior has been investigated for sandwich shells with different mechanical boundary conditions. Variations of natural frequencies and loss factors with temperature have also been examined for sandwich shells with two different core materials.