Seymour Bouvier is the son of Cecil Pâté and Hydrangia Bouvier. He is married to Chlorina Jones and is the father of Moonstar Bouvier-Jones.He is a cousin to Marge and cousin in law to Homer Simpson and uncle of Bart,Lisa and Maggie and Hugo (non-canon) Simpson.
In many cultures it is traditional for the wife to take her husband's surname when she marries, and any children born would also have the husband's surname. However, in The Simpsons Uncensored Family Album, Seymour is shown as having the surname Bouvier. This does not appear to be a middle name and it is unknown what circumstances led to Seymour having a different last name than his father.