The Icelandic striker joined Wanderers from fellow Tippeligaen side Lillestrom in the summer of 2012 and, having struggled to firmly establish himself at Molineux, has returned to Norway until the end of 2014.
Siguardson will remain with Molde until the conclusion of their forthcoming league season in November.
Head coach Kenny Jackett said: "Bjorn has expressed a desire to go and play abroad again.
"He feels that the football will suit him better than in England and in particular League One.
"He is going to a very good club in Molde for a year as he tries to re-establish and build his career again."