ENEthic minorities as a subject of historical research have been ignored for a long time. However, the popularity of social history among historians gradually increased after the collapse of the Soviet Union. The census of Lithuanian public organizations was conducted in 1931. It was the only census of such type in the interwar period. Even though the census of 1931 is presented in Lithuanian historiography, a comprehensive analysis of reflection of ethic minorities is lacking. The main aim of this article is to fill up this existing gap by means of systematic analyses of the census of Lithuanian public organizations. This study is based on the surviving documents of the census and additional statistical sources, such as the population census of 1923 as well as various volumes of Statistical Yearbook of Lithuania. Moreover, an in-depth analysis of historiography was conducted. The initial stage of research determined the following: a) the most extensive network of public organizations was developed by Jews. Jews were represented in ten out of twelve organizational categories. There are no doubts about the overwhelming domination of Jews in the organizational network; b) Russians, Poles, Germans, Latvians, Belarusians and some smaller ethic groups were involved in the cultural sphere while political activity was left outside for various reasons; c) the research revealed a specific orientation of different minorities. For instance, Russians and Poles were active in religious movements while Germans were involved in abstinence organizations. Comprehensive analysis of the factors which could have stimulated the involvement in public organizations revealed an exclusive role of a city/town. The majority of organizations were located in the centre of the district. By contrast, rural areas were less active. It was due to a different lifestyle as well as distinct social links among community members, etc.This study also determined that age, literacy, sex, livelihood had an impact on different activity among ethic minorities, however, to a lesser extent compared to the city/town factor. The investigation of organizations’ register books and census data revealed information about a different development of organizations which did or did not have headquarters. The most intensive network development of self-contained organizations without headquarters occurred in the first part of the third decade. Meanwhile, the advancement of organizations with headquarters reached the highest levels in the second part of the third decade. To sum up, the network of public organizations of ethnic minorities in Lithuania was fully developed by the third decade.