Sophie of Bar (c. 1004 or 1018 –January 21 or June 21, 1093) was a daughter of Duke Frederick II of Upper Lotharingia (died 1026/1027), count of Bar, and Mathilda of Swabia. She was Countess of Bar between 1033 and 1092, in succession of her childless brother, Duke Frederick III of Upper Lotharingia (died 1033). Her sister Beatrix (died 1076) married Boniface, margrave of Tuscany, and remarried after his death with Godfrey III, Duke of Lower Lotharingia.

She married Count Louis of Montbéliard (1019–1071 or 1073). Their son Count Thierry II of Bar-Montbéliard (1045–1105) succeeded to the county of Bar.

Their other children were:

Bruno
Louis, cited in 1080
Frederick (died 1092), marquis of Suze
Sophie, married to Folmar, count of Froburg
Beatrice (died 1092), married to Berthold I of Zähringen (died 1078), duke of Carinthia
Mathilde, married to Hugh of Dagsburg (died 1089)