Sun dogs (also called phantom suns or mock suns) are another natural light phenomena that can often be seen in parts of Lapland on crisp, cold, and sunny days. Scientifically speaking, sun dogs are parhelia or parhelion - an atmospheric phenomenon that occurs when sunlight interacts with or reflects against ice crystals in the atmosphere, creating a pair of bright rainbow-like spots on both sides of the sun. They often occur simultaneously with a visible ring above the sun know as a 22° halo. Sun dogs occur at the same elevation above the horizon as the sun and are more often visible when the sun is low (sunrise or sunset).

Sun dogs occur in many places around the world so are not unique to Lapland necessarily, however, they are an additional exciting natural phenomena to observe when visiting, in addition to viewing the northern lights, midnight sun, polar night (kaamos), moon dogs, or autumn colors of ruska.