Adelaide of Leuven (died c. 1158) was the wife of Simon I, Duke of Lorraine (1076–1138). She was the daughter of Henry III of Leuven and his wife Gertrude of Flanders. After the death of her husband, Adelaide retired to a Cistercian abbey.
The children of Simon I and Adelaide included:
- Matthias I, Duke of Lorraine
- Robert, Lord of Floranges
- Agatha of Lorraine, wife of Renaud III, Count of Burgundy
- Hedwige, wife of Frederick III, count of Toul
- Bertha, wife of Margrave Hermann III of Baden
- Mathilde, wife of Gottfried I, Count of Sponheim
- Baldwin
- John