During last years, direct evidence about oscillations in different coronal structures has been obtained thanks to the detailed observations made by SoHO and TRACE. With the help of magnetohydrodynamic (MHD) wave theory, we can explain these observations as due to the excitation and propagation of MHD waves in the solar corona. In spite that there are many solar coronal structures in which oscillations have been detected (prominences, loops, plumes, coronal holes, etc.), in the following we will concentrate on transverse oscillations of coronal loops, reviewing some theoretical models developed to understand these oscillations in terms of MHD waves.