Sophus Otto Müller (24 May 1846 - 23 February 1934) was a Danish archaeologist.^[1]

He was born in Copenhagen, the son of C. Louis Müller. Sophus studied classical philology at Copenhagen University, graduating cand.philol. in 1871. He conducted a study trip to Germany, Switzerland, and Italy during 1872-73. He became a teacher until 1876, while assisting at the National Museum of Denmark. He was hired by the museum in 1878, and graduated with a Ph.D. in 1880 with the essay Dyreornamentiken i Norden.^[2]

He discovered the single burial mounds of central Jutland. This discovery was the first proof of Middle Neolithic Periods in Scandinavia.^[3]

After 1881 he was secretary at the Royal Archaeological Society and edited Aarböger for Nordisk Oldkyndighed and Nordiske Fortidsminder. In 1885, he was an inspector at the museum,^[4] then, when the museum was being re-organized as the Danish National Museum, he was the director of the ancient history section in 1892. In 1895, he was named the museum's director.^{[2] [5]}

In 1888, his two-volume work Ordning af Danmarks Oldsager (The Arrangement of Denmark's Antiquities) was published.^[4] He wrote a prehistory of Denmark, which was published as Vor Oldtid (Our Prehistory) in 1897.^[2]He retired from the museum in 1921.

Müller became a Knight of Order of the Dannebrog 1889, Dannebrogsmand 1901, Commander of 2nd degree 1913 and of 1st degree 1921. He died at Frederiksberg and was buried at Skoven Kirkegård. ^[1]

• Gundestrup cauldron