The Janeway family consisted of Kathryn Janeway, her father, mother, sister, an aunt Martha, a grandmother, and a grandfather.
Ancestors included Henry Janeway, who took Shannon O'Donnel as his wife after being widowed. Henry Janeway also had a son by his previous wife, Jason. They had several children and grandchildren, including Kieran. According to family legend, O'Donnel was "the first of a long line of Janeway explorers."(VOY: "11:59")
Kathryn Janeway also had three children with Tom Paris while they were in a lizard-like form. The children were left behind on a planet where they were born. (VOY: "Threshold") Kathryn Janeway was at one point engaged to Mark Johnson, but he married someone else after coming to believe she was dead. (VOY: "Hunters")
In 2373, after the USS Voyager became stranded in the Delta Quadrant, Kathryn Janeway began to write letters to her fiancé and her family. In 2374, she updated them, as there was a possibility that messages could be sent home via a Hirogen communication relay station Voyager had located. (VOY: "Message in a Bottle")