Kathleen Sky (born Kathleen McKinney, August 5, 1943) is the pen name of Kathleen McKinney Goldin, an American science fiction and fantasy author. Her pen name is her former married name from her marriage to first husband Karl Sky. From 1972 to 1982 she was married to fellow author and collaborator Stephen Goldin. Most of her fiction is romantic in nature. Her books include Vulcan! and Death's Angel, two of the earliest original novels based on the 1960s Star Trek TV series.