The first known three-dimensional (3-D) vibration solutions for cantilevered skewed helicoidal thick shells are presented. the Ritz method is used to minimize the 3-D elasticity-based dynamical energies with displacements approximated by mathematically complete polynomials satisfying the clamped boundary conditions exactly. the accuracy of the method is established by convergence studies explicitly showing the effects of thickness ratio and twist angle in the presence of shell skewness. Results obtained using the present Ritz method are compared with those obtained in a detailed 3-D finite element analysis, where the correctness of various solid element discretizations are examined. This work offers some useful 3-D vibration results for the title problem with which future solutions drawn from higher-order thick shell theories may be compared.