As a first endeavor, the free vibration behavior of functionally graded carbon nanotubes-reinforced composite (FG-CNTRC) skewed cylindrical panels, as a most general geometry of panels in practical applications, is investigated. The first-order shear deformation shell theory is used to model the kinematics of deformations, and Hamilton’s principle is applied to drive the differential governing equations and the related boundary conditions. An analytical transformation together with the differential quadrature method, namely transformed differential quadrature method, is employed to discretize the governing equations subjected to general boundary conditions. This method offers superior practicality and applicability in directly discretizing the governing differential equations for an arbitrary physical domain. The correctness of the computational method is investigated through several numerical examples that include FG-CNTRC skew plates, homogeneous skewed cylindrical panels and FG-CNTRC cylindrical panels. Eventually, the effects of geometrical shape parameters like thickness/radius-to-length and aspect ratios, different distributions and volume fractions of CNTs and boundary conditions on the non-dimensional frequency parameters of the FG-CNTRC skewed cylindrical panels are studied.