Appeasement is a diplomatic policy aimed at avoiding war by making concessions to an aggressor. Historian Paul Kennedy defines it as "the policy of settling international quarrels by admitting and satisfying grievances through rational negotiation and compromise, thereby avoiding the resort to an armed conflict which would be expensive, bloody, and possibly dangerous." Kennedy's definition has been widely cited by scholars. Appeasement was used by European democracies in the 1930s who wished to avoid war with the dictatorships of Germany and Italy, bearing in mind the horrors of World War I.

The term is most often applied to the foreign policy of the British Prime Minister Neville Chamberlain towards Nazi Germany between 1937 and 1939. His policies of avoiding war with Germany have been the subject of intense debate for seventy years among academics, politicians and diplomats. The historians' assessments have ranged from condemnation for allowing Hitler to grow too strong, to the judgement that he had no alternative and acted in Britain's best interests. At the time, these concessions were widely seen as positive, and the Munich Pact among Germany, Britain, France and Italy prompted Chamberlain to announce that he had secured "peace for our time".

Arthur Neville Chamberlain FRS (18 March 1869 – 9 November 1940) was a British Conservative politician who served as Prime Minister of the United Kingdom from May 1937 to May 1940. Chamberlain is best known for his appeasement foreign policy, and in particular for his signing of the Munich Agreement in 1938, conceding the Sudetenland region of Czechoslovakia to Germany. When Adolf Hitler continued his aggression by invading Poland, Britain declared war on Germany on 3 September 1939, and Chamberlain led Britain through the first eight months of the Second World War.

After working in business and local government and after a short spell as Director of National Service in 1916 and 1917, Chamberlain followed his father and older half-brother in becoming a Member of Parliament in the 1918 general election at age 49. He declined a junior ministerial position, remaining a backbencher until 1922. He was rapidly promoted in 1923 to Minister of Health and then Chancellor of the Exchequer. After a short Labour-led government, he returned as Minister of Health, introducing a range of reform measures from 1924 to 1929. He was appointed Chancellor of the Exchequer in the National Government in 1931.