2nd Congress
- 2nd Congress of the Communist Party of India
- 2nd Congress of the Philippines
- 2nd Congress of the Russian Social Democratic Labour Party
- 2nd Congress of the Workers' Party of North Korea
- 2nd National Congress of the Chinese Communist Party
- 2nd National Congress of the Kuomintang
- 2nd National Congress of the Lao People's Revolutionary Party
- 2nd National People's Congress
- 2nd United States Congress
- 2nd World Congress of the Comintern
- International Socialist Labor Congress of Brussels, 1891
- Lausanne Congress (1867)
- Second International Congress of the History of Science