Adelaide of Rheinfelden (or Adelaide of Swabia) (German: Adelheid) (1060s – May 1090), was the daughter of Rudolf of Rheinfelden; and wife of King Ladislaus I of Hungary. She was a Queen Consort of Hungary.
Around 1077/8 Adelaide married Ladislaus I of Hungary, a member of the Árpád dynasty. Ladislaus agreed to support Rudolf in his struggle for the throne against Henry IV of Germany. In 1079 Adelaide’s mother died, followed in 1080 by her father, who fell at the Battle of Elster.
In 1081 Pope Gregory VII wrote to Adelaide, urging her to encourage her husband to support monasteries and be generous to the poor and the weak.