Robert Stewart or Stuart, 1st Duke of Albany (c. 1340 - 3 September 1420) was a Scottish nobleman, who served as regent (at least partially) to three different Scottish monarchs. He was also created Earl of Menteith (28 February 1361), Earl of Fife (1361; resigned in 1372), Earl of Buchan (1394; resigned in 1406) and Earl of Atholl (1403, for the duration of Robert III's life only), in addition to his 1398 creation as Duke of Albany.
He was the illegitimate son of King Robert II of Scotland and Elizabeth Mure of Rowallan. He was legitimatised in 1349 upon his parents' marriage. The elder Robert had many children, the eldest of whom was John Stewart, Earl of Carrick. In 1361, Stewart married Mary Graham, Countess of Menteith, with whom he had several daughters and one son, Murdoch Stewart, 2nd Duke of Albany; his sister-in-law's claim to the Earldoms of Menteith and Fife allowed him to assume those titles after marriage. Robert was married a second time, to Muriella de Keith, with whom he had two sons.
During their father's reign, the Duke of Albany and Lord Carrick served as regents for their infirm father, with Albany serving as High Chamberlain of Scotland; during this time, he also led several military expeditions and raids into England. However, in 1389, Lord Carrick was incapacitated in an accident, and this "sickness of the body" caused control of the kingdom to devolve to David Stewart, Duke of Rothesay (the first dukedom created in the Scottish Peerage), the heir to the throne after Carrick acceded as Robert III. However, the English soon invaded Scotland, and several important events took place, fomenting serious differences between Albany and Rothesay, and in 1402 the latter duke mysteriously died of starvation at Falkland Palace. After the death of Robert III, Albany served as regent to James I.
He died in Stirling Castle and is interred in Dunfermline Abbey in Fife.