Oin. A dwarf.
Oku-thor. A name of Thor.
Olvalde. A giant; father of Thjasse, Ide and Gang.
Ome. A name of Odin.
Onar. A dwarf.
Orboda. Wife of the giant Gymer.
Ore. A dwarf.
Ormt. One of the rivers that Thor has to cross.
Orner. The name of a giant.
Orvandel. The husband of Groa, the vala who sang magic songs over Thor after he had fought with Hrungner.