Erik Hakonsson, also known as Eric of Hlathir or Eric of Norway (Old Norse: Eiríkr Hákonarson; 960s – 1020s), was Earl of Lade, Governor of Norway and Earl of Northumbria. He was the son of Earl Hákon Sigurðarson and brother of the legendary Aud Haakonsdottir of Lade. He participated in the Battle of Hjörungavágr, the Battle of Svolder and the conquest of England by King Canute the Great.

Eric is referred to in various ways in the medieval sources and by modern scholars. He most commonly witnessed charters as Yric dux ("Duke Eric") but his name is also spelled Yric, Yrric, Iric, Eiric or Eric in 11th-century Latin and Old English sources. In Old Norse sources, using normalized orthography, he is most commonly Eiríkr jarl ("Earl Eric") or Eiríkr jarl Hákonarson, but sometimes as Eirekr. Modern historians usually use a variant of Eiríkr/Eirik/Eric and his patronym, Hákonarson/Hakonarson/Hakonson, meaning "son of Haakon". In modern Norwegian, it would be Eirik Håkonsson. Some English works prefer Eric of Hlathir, referring to his Norse earldom, or Eric of Norway.

Principal sources on Eric's youth are Fagrskinna and Heimskringla. They relate that Eric was the son of Hákon Sigurðarson and a woman of low birth whom Hákon bedded during a sojourn in Oppland. Hákon cared little for the boy and gave him to a friend of his to raise. On one occasion when Eric was eleven or twelve years old he and his foster father had harboured their ship right next to earl Hákon. Then Hákon's closest friend, Skopti, arrived and asked Eric to move away so that he could harbour next to Hákon as he was used to. When Eric refused, Hákon was infuriated by the boy's pride and sternly ordered him away. Humiliated, Eric had no choice but to obey. In the following winter he avenged the humiliation by chasing down Skopti's ship and killing him. This was Eric's first exploit, as commemorated by his skald Eyjólfr dáðaskáld who mentions the incident in his Bandadrápa. The sagas say that after killing Skopti, Eric sailed south to Denmark where he was received by king Harald Bluetooth. After a winter's stay in Denmark, Harald granted Eric earldom over Romerike and Vingulmark - areas in the south of Norway long under Danish influence. In Heimskringla this information is supported with a somewhat vague verse from Bandadrápa.

The Battle of Hjörungavágr was Eric's first major confrontation. The battle was fought at sea, between the earls of Lade and a Danish invasion fleet. The battle is described in the Norse kings' sagas—such as Heimskringla—as well as in Jómsvíkinga saga and Saxo Grammaticus' Gesta Danorum. Those late literary accounts are fanciful but historians believe that they contain a kernel of truth. Some contemporary skaldic poetry alludes to the battle, including verses by Þórðr Kolbeinsson and Tindr Hallkelsson.

Hákon Sigurðarson was a strong believer in the Old Norse gods, and when King Harald Bluetooth attempted to force Christianity upon him, Haakon broke his allegiance to Denmark. A Danish invasion force was defeated at the battle of Hjörungavágr in 986. According to Heimskringla, Eric, apparently reconciled with his father, commanded 60 ships in the battle and emerged victorious. After the battle he gave quarter to many of the Jomsvikings, including Vagn Ákason.

In 995, as Óláfr Tryggvason seized power as King of Norway, Eric was forced into exile in Sweden. He allied himself with King Olof of Sweden and King Sweyn whose daughter, Gyða, he married. Using Sweden as his base he launched a series of raiding expeditions into the east. Harrying the lands of King Vladimir I of Kiev, Eric looted and burned down the town of Staraya Ladoga (Old Norse: Aldeigja). There are no written continental sources to confirm or refute this but in the 1980s, Soviet archaeologists unearthed evidence which showed a burning of Ladoga in the late 10th century. Eric also plundered in western Estonia (Old Norse: Aðalsýsla) and the island of Saaremaa (Old Norse: Eysýsla). According to the Fagrskinna summary of Bandadrápa he fought Vikings in the Baltic and raided Östergötland during the same time.

In the Battle of Svolder in 1000, Eric, Sweyn, and Olof ambushed king Óláfr Tryggvason by the island of Svolder. The place cannot now be identified, as the formation of the Baltic coast has been much modified in the course of subsequent centuries. Svolder was an island probably on the North German coast, near Rügen.

During the summer, King Olaf had been in the eastern Baltic. The allies lay in wait for him at the island of Svolder on his way home. The Norwegian king had with him seventy-one vessels, but part of them belonged to an associate, Jarl Sigvaldi, a chief of the Jomsvikings, who was an agent of his enemies, and who deserted him. Olaf's own ships went past the anchorage of Eric and his allies in a long column without order, as no attack was expected. The king was in the rear of the whole of his best vessels. The allies allowed the bulk of the Norwegian ships to pass, and then stood out to attack Olaf.