Andreas Aagesen (1826 - 1879) was a Danish jurist.
He was educated for the law at Christiania (now Oslo) and Copenhagen, and interrupted his studies in 1848 to take part in the first Schleswig war, in which he served as the leader of a reserve battalion. In 1855 he became professor of jurisprudence at the University of Copenhagen. In 1870 he was appointed a member of the commission for drawing up a maritime and commercial code, and the navigation law of 1882 is mainly his work.
In 1879 he was elected a member of the Landsting (Upper House of the Danish Parliament); but it is as a teacher at the university that he won his reputation. Among his numerous juridical works may be mentioned: Bidrag til Læren om Overdragelse af Ejendomsret, Bemærkinger om Rettigheder over Ting (Copenhagen, 1866, 1871-1872); Fortegnelse over Retssamlinger, Retslitteratur i Danmark, Norge, Sverige (Copenhagen, 1876). Aagesen was Hall's successor as lecturer on Roman law at the university, and in this department his researches were epoch-making. All his pupils were profoundly impressed by his exhaustive examination of the sources, his energetic demonstration of his subject and his stringent search after truth. His noble, imposing, and yet most amiable personality won for him, moreover, universal affection and respect.