Baldwin VI of Flanders (c. 1030 – 17 July 1070) was briefly Count of Flanders, from 1067 to 1070. He was also (as Baldwin I) count of Hainaut from 1051 to 1070.
He was the eldest son of Baldwin V of Flanders and Adele, a daughter of king Robert II of France.
In 1051 he married Richilde, Countess of Mons and Hainaut, widow of count Herman of Mons. By this marriage Flanders took control of Hainaut (at that moment still a conglomerate of the county of Mons, the margraviate of Valenciennes and the southern part of the landgraviate of Brabant).
Baldwin's early death left Flanders and Hainaut in the hands of his young son Arnulf III, with Richilde as regent. The countship was soon usurped by Baldwin's brother Robert the Frisian, who became count Robert I of Flanders. The young Arnulf III was killed the next year at the Battle of Cassel (1071) and Baldwin's younger son eventually became Baldwin II of Hainaut.
| Preceded by Baldwin V |
Count of Flanders 1067–1070 |
Succeeded by Arnulf I/III |
| Preceded by Herman, Count of Mons |
Count of Mons 1051–1070 |
|
| Preceded by Richilde, Countess of Mons and Hainaut |
Count of Hainaut 1051–1070 |
Succeeded by Arnulf III, Count of Flanders |