Viggo Olfert Fischer Kampmann (21 July 1910 – 3 June 1976) was the leader of the Danish Social Democrats and Prime Minister of Denmark from 19 February 1960 until 3 September 1962. His cabinet before the 1960 election was called the Cabinet of Viggo Kampmann I and the cabinet he formed after that election was called the Cabinet of Viggo Kampmann II. Before becoming Prime Minister he was Finance Minister from 30 September 1953 to 21 February 1960 in the Cabinet of Hans Hedtoft II and the Cabinet of H. C. Hansen I and II.
Kampmann was born in Frederiksberg Denmark. He came from an academic background and was the first academic to rise to a high rank in the Danish Social Democratic Party. Before becoming Minister of Finance he worked in the newly formed economical secretariat as the Financial Minister's closest adviser. He was first elected to the Folketing in 1953.
When Prime Minister and Social Democrat H. C. Hansen died in February 1960 Kampmann succeeded him, creating the Cabinet of Viggo Kampmann I. H. C. Hansen had cooperated with the Danish Social Liberal Party and Retsforbundet, but Viggo Kampmann had problems working with Retsforbundet. After the 1960 Danish parliamentary election Retsforbundet failed to get into Folketinget and the Danish Social Liberal Party went from 14 to 11 mandates. But the Social Democrats gained 6 mandates to 76, and Viggo Kampmann was able to form a minority government with the Danish Social Liberal Party, the Cabinet of Viggo Kampmann II.
In 1962 the oms, the precursor to the moms, was introduced.
Kampmann was one of the most intelligent and knowledgeable Danish Prime Ministers, though his conduct in office was erratic. Through most of his adult life he suffered from bipolar disorder, and in his darker moments he tended towards alcoholism and frequently 'disappeared' from view for days at a time, leaving the government without its head.
Viggo Kampmann resigned on 3 September 1962 after a series of heart attacks, and was succeeded by Jens Otto Krag as leader of the Social Democrats and as Prime Minister. In retirement he worked as a political commentator and head of the Press Complaints Commission. Viggo Kampmann died in Store Torøje on 3 June 1976.