Per Lasson Krohg (18 June 1889 - 3 March 1965) was a Norwegian artist. He is most frequently associated with the mural he created for the United Nations Security Council Chamber, located in the United Nations building in New York City.
Per Krohg was born in Åsgårdstrand, Norway, the son of painters Christian Krohg and Oda Krohg. The family lived in Paris, where Per Krohg grew up. He showed artistic talent early, and studied first with his father (from 1903 to 1907), then with Henri Matisse (from 1909 to 1910). In the early years he worked as a newspaper illustrator and taught tango in Paris.
Krohg's work as an artist covered a wide field, from paper drawings, illustrations, and posters to set design, sculpture, and monumental paintings. After returning to Norway in 1930 he taught at the National College of Art and Design in Oslo. During the Second World War, he was a forced laborer at the Veidal Prison Camp. In 1946 he was appointed professor at the National Art Academy, and served as its director from 1955 to 1958. Among others, his students included artists Frithjof Tidemand-Johannessen and Tulla Blomberg Ranslet. 
Krohg created the murals for the United Nations Security Council Chamber, located in the United Nations building in New York City. He adorned many other public buildings with large frescoes, including the Physics and Chemistry Buildings at the University of Oslo and the Oslo City Hall. He is represented with 6 works in the collection at the National Gallery of Denmark. 
In 1950 he received the King's Medal of Merit in gold, and 1955 he was appointed Commander of the Order of St. Olav. From 1936 he was a member of the Swedish Royal Academy of Fine Arts in Stockholm and in 1948 he was awarded the Prince Eugen Medal.
He was married twice. In 1915 he married textile artist Cécile Marie ("Lucy") Vidil (1891-1977). Their marriage was dissolved in 1934. He was married in 1934 to Ragnhild Helene Andersen (1908-1972). He was the father of Norwegian artist Guy Krohg (1917-2002).