The Left Front (Bengali: বামফ্রন্ট, transliterated bamfront) is an alliance of political parties in the Indian state of West Bengal. It was formed in January 1977, the founding parties being the Communist Party of India (Marxist), All India Forward Bloc, the Revolutionary Socialist Party, the Marxist Forward Bloc, the Revolutionary Communist Party of India and the Biplabi Bangla Congress. Other parties joined in later years, most notably the Communist Party of India.
The Left Front ruled the state for seven consecutive terms 1977–2011, five with Jyoti Basu as Chief Minister and two under Buddhadev Bhattacharya. The CPI(M) is the dominant force in the alliance. In the 2011 West Bengal Legislative Assembly election the Left Front failed to gain a majority of seats and left office. As of 2016 Biman Bose is the Chairman of the West Bengal Left Front Committee.
The Left Front has its roots in various past platforms of collaboration of West Bengal left parties and anti-Indian National Congress forces. Such such examples were the United Left Front, the People's United Left Front and the United Front that governed West Bengal 1967–1971. However, ahead of the March 1977 Lok Sabha election the left parties under the leadership of CPI(M) decided to form an alliance just amongst themselves, based on past negative experiences in collaboration with centrist anti-Congress forces. The Left Front was set up as the repressive climate of the Emergency was relaxed in January 1977. The six founding parties of the Left Front, i.e. the CPI(M), the All India Forward Bloc, the Revolutionary Socialist Party, the Marxist Forward Bloc, the Revolutionary Communist Party of India and the Biplabi Bangla Congress, articulated a common programme. The Left Front contested the Lok Sabha election in an electoral understanding together with the Janata Party.