Duke Erik Birgersson (c. 1250 – 17 December 1275) was a Swedish duke.
His father was Birger Jarl, the ruler of Sweden from 1250–66, and his mother was Ingeborg of Sweden.
In the conflict between his elder brothers Valdemar and Magnus he sided with Magnus. When Magnus had won and been proclaimed king in 1275, he made Erik duke of Småland. Erik was buried at Varnhem together with his father and his father’s second wife.
According to the Magnúss saga lagabœtis, Erik called himself "Eirek allz-ekki" because he had no title. Only when Magnus III became king did Erik change his title and call himself "Duke".
When Birger Jarl's grave in Varnhem Abbey was opened and examined in May 2002, osteologist Torbjörn Ahlström from Lund University confirmed that the tomb contained the remains of three people – probably Birger Jarl, his second wife Matilda of Holstein, and Erik. His father's skeleton shows that he was about 172 cm long, while Erik was a few inches longer but with a much thinner build. His muscular attachments were poorly developed. In the vertebrae and sternum there were some signs of pathological changes, and he would have been 25 years old when he died in 1275.