The Lithuanian Catholic Federation Ateitis (literally, 'future') is a youth organization in Lithuania uniting Catholic-minded schoolchildren, university students, and alumni. Members of the Ateitis Federation are known as ateitininkai. The organization was established in 1910 and aims for integral development of young people enabling them to be effective apostles of Christ and creative agents capable of changing society according to Christian values. For historical reasons another central aim is to preserve the national heritage and culture of Lithuania. The five principles of Ateitis are: Catholicism, community spirit, social responsibility, education and patriotism. The motto of Ateitis is To Renew All Things in Christ (Latin: Omnia Instaurare in Christo, Lithuanian: Visa atnaujinti Kristuje).

Ateitis works for integral development of young people enabling them to be effective apostles of Christ and creative agents capable of changing society according to Christian values. The five principles of Ateitis are: Catholicism, community spirit, social responsibility, education and patriotism. Ateitis is member of the international umbrella of Catholic youth organizations Fimcap and is interesting in engaging with simillar organziations in Poland and Ukraine because international relations helps in formation of our young members, enables them to be a part of our common Church.