The evaluation of wave transmission in structural junctions is an important part of the study of structure-borne noise. In this paper, a method for calculating the wave transmission through plate and beam junctions is described. It is assumed that the joint element is an elastic block. Linear approximation of the displacement field is introduced to derive equations which describe the dynamic response of the joint element. A numerical example is presented to illustrate the method. The example involves the analysis of vibratory power transmission through T-junction of three plates. Wave transmission theory is used to find the complex-wave amplitudes for transmitted and reflected waves. The complex-wave amplitudes are used to calculate the transmission efficiencies. This example also includes a comparison of the presented method with other methods for evaluating the wave transmission through junctions. Results of calculations show that the effect of three-dimensional deformation of a junction is important in the mid- and high-frequency range.