The Finnish term Heimosodat (singular heimosota)[a][1] refers to a series of armed conflicts and private military expeditions in 1918–1922 into areas of the former Russian Empire that bordered on Finland and were inhabited in large part by other Finnic peoples.

According to Aapo Roselius, about 10,000 volunteers from Finland took part in the armed conflicts mentioned below.

Estonia, the closest and numerically largest "kindred nation", had gained its independence at the same time, but had fewer resources, fewer institutions ready to support its attained position, and more Bolshevik Russian troops within its borders.

For the two next decades, Finns participated at a relatively high rate in nationalistic activities (e.g. Karelianism and Finnicization of the country and its institutions).

The strenuous five-year period 1939–45 of total war — which also mostly unified the nation — reduced this enthusiasm.