Donald III of Scotland (c. 1033 - 1099) was king of Scotland from 1093 to 1094 and 1094 to 1097. He is also known as Donaldbane, Donalbain, or Donald Bane. He was born about 1033 and became Mormaer (or Earl) of Gowrie about 1060. He was the son of Duncan I, brother of the previous king Malcolm III, and uncle of his successor Duncan II.

Donald III took the throne of Scotland in 1093 on the death of his brother Malcolm III, in a joint rule with his nephew Edmund I. No record exists that indicates that Donald was ever crowned. Malcolm's son Duncan II deposed Donald III in May, 1094. Duncan II died the following November and Donald III retook the throne jointly with his nephew King Edmund, with Donald ruling the north of the kingdom and Edmund ruling the south. Donald III and Edmund were deposed in favour of King Edgar in 1094.

Donald died, imprisoned at Rescobie, Angus, in 1099.

At some point in his life Donald married, and had a daughter, Bethoc, through this marriage. Bethoc married and had children of her own. However, Bethoc and her descendants never made a bid for the Scottish throne.