This study demonstrates the effectiveness of functionally graded coatings in the vibration of sandwich truncated conical shells. First order shear deformation shell theory (FOSDT) and Donnell kinematics assumptions are used to establish the governing equations. The problem is solved for piecewise and continuous through-the-thickness coatings stiffness variations. The closed-form solution is obtained for frequency parameters of homogeneous truncated conical shells coated by functionally graded (FG) layers within the FOSDT. The analysis is extended to account for the influences of transverse shear deformations and functionally graded material (FGM) layers on the frequency parameters of sandwich truncated conical shells. Parametric studies are conducted for two configurations, different volume fraction index and different geometrical parameters of FGM sandwich truncated cones. (C) 2017 Elsevier Ltd. All rights reserved.