Alexander I (c. 1078 – April 23 1124), called "The Fierce", king of Scotland, was the fourth son of Malcolm Canmore by his wife (St) Margaret, grand-niece of Edward the Confessor. He was named in honor of Pope Alexander II.

On the death of his brother Edgar in 1107 he succeeded to the Scottish crown; but, in accordance with Edgar's instructions, he inherited only a part of its possessions. By a partition, the motive of which is not quite certain, the districts south of the Forth and Clyde were erected into an earldom for Alexander's younger brother, David.

Alexander, dissatisfied, sought to obtain the whole, but without success. A curious combination of the fierce warrior and the pious churchman, he manifested the one aspect of his character in his ruthless suppression of an insurrection on behalf of the descendants of Lulach in his northern dominion (thus gaining for himself the title of "the Fierce"), the other in his munificent foundation of bishoprics and abbeys. Among the latter were those of Scone and Inchcolm.

In 1107, he married Sybilla, an illegitimate daughter of Henry I of England. The exact date and the location of the marriage are not recorded. Sybilla died in unrecorded circumstances near a lake on the Island of the Woman (Eilean nam Bain) in July, 1122. The marriage produced no children.

Alexander's strong championing of the independence of the Scottish church involved him in struggles with both of the English metropolitan sees. He died on April 23, 25 or 27, 1124 at his court at Stirling; his brother, David I succeeded him. The historian John of Fordun said of him: "[Alexander] was humble and courteous to the clergy, but, to the rest of his subjects, terrible beyond measure."