Magnus II; Swedish: Magnus Henriksson (died 1161) was a Danish lord and King of Sweden between 1160 and 1161. He is often seen by posterity as a usurper.
The mother of Magnus was Ingrid Ragvaldsdotter, a granddaughter of King Inge I of Sweden. His father was the Danish lord Henrik Skatelår, son of an illegitimate son of king Sweyn II of Denmark. After Henrik's death, Ingrid remarried thrice, with Harald Gille of Norway, then Ottar Birting, and finally Arne from Stårheim. Magnus therefore had kinship ties with the royalty of the three Nordic kingdoms. He was married to his stepsister Bridget Haraldsdotter, a daughter of Harald Gille who had previously been married to the powerful jarl in Västergötland, Karl Sunesson. Magnus is first mentioned in 1148 when he witnessed a document issued by King Sweyn III of Denmark.
Magnus was a claimant to the much-competed throne of Sweden. In 1156 he allegedly bribed a trusted servant of King Sverker I to assassinate him. A few years later, according to a legendary source, he allied with a certain chief in the country, possibly Sverker's son Karl. He then ambushed and killed Eric IX of Sweden (later to be known as Eric the Saint) when he left the church at Östra Aros near Uppsala on May 18, 1160. After this feat Magnus reigned as king over most of Sweden, but apparently not Östergötland, which was ruled by Karl Sverkersson since c. 1158. He is, however, mentioned in the short chronicle of the Westrogothic law, implying that he was recognized in Västergötland. Magnus appointed his brother Ragnvald as jarl and provided refuge to his uterine brother Orm when their brother King Inge the Hunchback was killed in Norway. Otherwise not much is known about his reign, except that he donated land to Vreta Abbey.