4th Congress
- 4th Congress of the Communist Party of Yugoslavia
- 4th Congress of the Philippines
- 4th Congress of the Russian Social Democratic Labour Party
- 4th Congress of the Workers' Party of Korea
- 4th National Congress of the Chinese Communist Party
- 4th National Congress of the Communist Party of the Philippines
- 4th National Congress of the Kuomintang
- 4th National Congress of the Lao People's Revolutionary Party
- 4th National People's Congress
- 4th United States Congress
- 4th World Congress of the Communist International
- Basel Congress (1869)
- International Socialist Workers and Trade Union Congress, London 1896