The article considers an aspect of the history of civil captivity during World War I which, by itself, had not been previously studied — i.e., influence of the internment policy on the situation of “enemy foreigners” families. Until recently, the historiography addressed only the situation of civilian prisoners, men of military age, while the situation of their families was only mentioned. Drawing on documents from the Russian and German archives, as well as on the published sources, including legislative acts, petitions of individuals, memoirs and diaries, a comparative analysis has been carried out of the policy of the authorities in Russia and Germany towards hostile state citizens and their family members. It is concluded that, although the policy of internment in Russia and Germany was not directed strictly against this group of enemy subjects, its very course had a significant impact on their situation. The formation of legal foundations of internment in the Russian Empire is considered. The article shows the changed approaches to internment of enemy subjects under the influence of situation at the front and situation of the individual front-line territories. It has been established that in a number of cases, it was required to deport from front-line areas not only men liable for military service — citizens of states fighting with Russia, but also their family members. In Germany, the rules for internment were unclear, but the established practice also affected the situation of women and children. In both states, when interning men of military age, family members often followed them to camps and places of deportation. The proximity of cultural, economic, and family ties between the citizens of Russia and Germany on the brink of the First World War resulted in a conflict between nationality and citizenship. Russian citizens in Germany, despite being of German origin, became hostile foreigners. The article analyzes the situation of interned family members in German camps. In some cases, there were organized schools for children. A wide variety of reasons caused the breakdown of family ties: different citizenship of family members, loss of loved ones in displacement, internment of some family members, while other remained at their place of residence. It is concluded that there are similarities, as well as differences in the methods of internment in Russia and Germany, which in both cases negatively affected the situation of the families of hostile state citizens.