Contrary to Durkheim’s idea about suicide during wartime, the Netherlands had high suicide rates in 1940 and 1945. To explain these findings, we propose the social integration theory, according to which, people who expect to be excluded from society are more likely to commit suicide. We examine this idea using individual-level data on suicide in the Netherlands during the Second World War, assuming that Jews expected to be excluded by the occupying German forces, whereas political delinquents expected punishment after the war. In support of our theory, we found high suicide rates among Jews at the beginning of the war and high suicide rates among political delinquents when the Netherlands was liberated. These findings support the proposed theory and call for refinement of Durkheim’s ideas.