Valdemar Birgersson (1239 – 1302), King of Sweden 1250 – 1275/1288/1302, was the son of princess Ingeborg Eriksdotter of Sweden and Birger Jarl, Earl Birger Magnusson of Bjälbo, who more or less ruled Sweden from 1248 under king Eric Ericsson the Lame his brother in law. When king Eric XI died in 1250, Valdemar was elected king, while Birger Jarl (perhaps) was on crusade in Finland.

Even after the coming of age of Valdemar in 1257 his father Jarl Birger held a grip over the country. After Birger's death in 1266 Valdemar came into conflict with his younger brother Jarl or Duke Magnus, who wanted the throne for himself.

Valdemar had a relationship with his Queen's sister Jutta (both of them princesses of Denmark) and had to go to Rome in order to get the Pope's forgiveness. In 1288 he was imprisoned by his brother Magnus, (later Magnus I of Sweden) who had usurped his throne, being elected king in 1275.

Valdemar was married four times and left several children by Queen Sophia (dead 1286).