The Interim Peace (Finnish: Välirauha, Swedish: Mellanfreden) was a short period in the history of Finland during the Second World War. The term is used for the time between the Winter War and the Continuation War, lasting a little over 15 months, from 13 March 1940 to 24 June 1941. The Moscow Peace Treaty was signed by Finland and the Soviet Union on 12 March 1940 and it ended the 105-day Winter War.

In the aftermath of the Winter War, both the Soviet Union and Finland were preparing for a new war while Stalin pressured the Finns politically. In early 1940 Finland sued for an alliance with Sweden but both the Soviet Union and Nazi Germany opposed it.^{[citation needed]} Nazi Germany occupied Denmark and Norway in April 1940 and defeated France in June 1940. Then, Stalin occupied the Baltic states. In 1941, Finland negotiated its participation in the Axis invasion of the Soviet Union.

The 1939 Molotov–Ribbentrop Pact clarified Soviet–German relations and enabled the Soviet Union to bring pressure to bear on the small Baltic republics and Finland, perhaps in order to better its strategic position in Eastern Europe in case of a widening of the war. The Baltic republics had to give in to Soviet demands for bases and troop transfer rights, but Finland continued to refuse. As diplomatic pressure had failed, arms were resorted to, and on 30 November 1939 the Soviet Union began the Winter War, an invasion of Finland.

The Winter War produced in Finns a rude awakening to international politics. Condemnation by the League of Nations and by countries all over the world seemed to have no effect on Stalin's policy. Sweden allowed volunteers to join the Finnish army, but did not send military support, and refused passage to French or British troops—which were in any event made ready in lower numbers than promised. Even right-wing extremists were shocked to find that Nazi Germany did not help at all, and also blocked material help from other countries.

The Moscow Peace Treaty, which ended the Winter War on 12 March 1940, was perceived as a great injustice. It seemed as if the losses at the negotiation table, including Viipuri (Finland's second-largest city [Population Register] or fourth-largest city [Church and Civil Register], depending on the census data), had been worse than on the battlefield. A fifth of the country's industrial capacity and 9% of its territory were lost. Of the 12% of Finland's population who lived in the lost territories, only a few hundred stayed, the remaining 420,000 moving to the Finnish side of the new border.

The Moscow Peace Treaty, signed on 12 March 1940, was a shock for the Finns. It was perceived as the ultimate failure of Finland's 1930s foreign policy, which had been based on multilateral guarantees for support from similar countries, first in the world order established by the League of Nations, and later from the Oslo group and Scandinavia. The immediate response was to broaden and intensify this policy. Binding bilateral treaties were now sought where Finland formerly had relied on goodwill and national friendship, and formerly frosty relations with ideological adversaries, such as the Soviet Union and the Third Reich, had necessarily to be eased.

Closer and improved relations were sought particularly with:

With exception for the case of Nazi Germany, all of these attempts turned out to meet critical obstacles—either due to Moscow's fear that Finland would slide out of the Soviet sphere of influence or due to general dynamics of the world war.