  In this review we consider various ring structures that are observed in
galaxies. Formation and evolution of the rings are interesting problems in
studies of galactic morphology. They are related to such fundamental aspects of
galactic evolution and dynamics as the nature and distribution of the dark
matter in galaxies, galactic interactions and internal secular evolution of
galactic substructures. A significant fraction of galactic rings forms in the
disks due to gravitational torques from bar-like patterns. In contrast to this
internally driven origin, the phenomenon of the polar-ring galaxies is closely
connected with the processes of intergalactic interactions and merging. A rare
class of collisional rings reveals the density waves triggered in the stellar
and gaseous disks after a strong head-on collision with a companion. We briefly
review the status of studies of gas kinematics in the rings of different
origin. We stress that velocity fields of the ionized gas obtained with the
Fabry-Perot interferometers provide a very important information for these
studies.
