Deer tick may refer to a few different Ixodes spp.:
Ixodes scapularis, the eastern North America black-legged tick Ixodes pacificus, the western North America black-legged tick Ixodes ricinus, the European tick sometimes called a "deer tick" or "sheep tick"
Other Deer Tick (band), American alt-rock-folk band
See also Lyme disease, a well-known disease spread by ticks Deer tick virus, causes encephalitis