Albert I (July 1255 – May 1, 1308) was a German king, duke of Austria, and eldest son of King Rudolph I of Habsburg.

The founder of the great house of Hapsburg was invested with the duchies of Austria and Styria, together with his brother Rudolph II, in 1282. In 1283 his father entrusted him with their sole government, and he appears to have ruled them with conspicuous success. Rudolph I was unable to secure the succession to the German throne for his son, and on his death in 1291, the princes, fearing Albert's power, chose Adolf of Nassau-Weilburg as king. A rising among his Swabian dependants compelled Albert to recognize the sovereignty of his rival, and to confine himself to the government of the Habsburg territories.

He did not abandon his hopes of the throne and, in 1298, was chosen German king by some of the princes, who were dissatisfied with Adolf. The armies of the rival kings met at Gollheim near Worms, where Adolf was defeated and slain, and Albert submitted to a fresh election. Having secured the support of several influential princes by extensive promises, he was chosen at Frankfurt on the July 27, 1298, and crowned at Aix-la-Chapelle on August 24.

Albert married Elizabeth, daughter of Meinhard II, count of Gorizia and Tyrol, who bore him six sons, including Rudolph III of Austria, Frederick I of Austria, Leopold I of Austria, Otto of Austria and Albert II of Austria, and five daughters. Although a hard, stern man, he had a keen sense of justice when his selfish interests were not involved, and few of the German kings possessed so practical an intelligence. He encouraged the cities, and not content with issuing proclamations against private war, formed alliances with the princes in order to enforce his decrees. The serfs, whose wrongs seldom attracted notice in an age indifferent to the claims of common humanity, found a friend in this severe monarch, and he protected even the despised and persecuted Jews. The stories of his cruelty and oppression in the Swiss cantons first appear in the 16th century, and are now regarded as legendary.

Albert sought to play an important part in European affairs. He seemed at first inclined to press a quarrel with France over the Burgundian frontier, but the refusal of Pope Boniface VIII to recognize his election led him to change his policy, and, in 1299, a treaty was made between Albert and Philip IV of France, by which Rudolph, the son of the German king, was to marry Blanche, a daughter of the French king. He afterwards became estranged from Philip, and, in 1303, was recognized as German king and future emperor by Boniface and, in return, admitted the right of the pope alone to bestow the imperial crown, and promised that none of his sons should be elected German king without the papal consent.

Albert had failed in his attempt to seize Holland and Zeeland, as vacant fiefs of the Empire, on the death of Count John I in 1299, but in 1306 he secured the crown of Bohemia for his son Rudolph on the death of King Wenceslaus III. He also renewed the claim which had been made by his predecessor, Adolf, on Thuringia, and interfered in a quarrel over the succession to the Hungarian throne. His attack on Thuringia ended in his defeat at Lucka in 1307 and, in the same year, the death of his son Rudolph weakened his position in eastern Europe. His action in abolishing all tolls established on the Rhine since 1250, led to the formation of a league against him by the Rhenish archbishops and the count palatine of the Rhine; but aided by the towns, he soon crushed the rising.

He was on the way to suppress a revolt in Swabia when he was murdered on May 1, 1308, at Windisch on the Reuss River, by his nephew John, afterwards called "the Parricide", whom he had deprived of his inheritance.