Reginald II of Bar (French: Renaut or Renaud) (died 25 July 1170) was a Count of Bar and Lord of Mousson from 1149 till his death. He was the son of Reginald I, Count of Bar and lord of Mousson, and Giselle of Vaudémont.
In 1135, he attended the Council of Hugh of Metz with his father and brother. He took part in the second crusade with his father and brother Theodoric in 1147. His father died during his return. He reestablished wars against his traditional enemies, the Duke of Lorraine and the bishop of Metz.
He was attacked in 1152, escaped to the Abbey of Saint-Mihiel and was excommunicated and had to make amends. In 1170, Reginald died, to be succeeded by his eldest son, Henry, as Count of Bar and Lord of Mousson.
He was married in 1155 to Agnes of Champagne (died 1207), daughter of Theobald II (IV), Count of Blois and Champagne and Matilda of Carinthia, and had the following issue:
| Preceded by Reginald I, Count of Bar |
Count of Bar 1150–1170 |
Succeeded by Henry I, Count of Bar |
| Preceded by Reginald I, Count of Bar |
Lord of Mousson 1150–1170 |
Succeeded by Henry I, Count of Bar |