2015 Bihar Legislative Assembly election

The Legislative Assembly election was held over five phases in the Indian state of Bihar through October–November 2015 before the end of the tenure of the prior Bihar Legislative Assembly on 29 November 2015.

In April 2015, the Janata Parivar Alliance group (a group of six parties – Samajwadi Party, Janata Dal (United), Rashtriya Janata Dal, Janata Dal (Secular), Indian National Lok Dal and Samajwadi Janata Party (Rashtriya)) announced their intention to fight the election, with Nitish Kumar as their Chief Ministerial candidate. The Janta Parivar was joined by the Muslim League and the Nationalist Congress Party. This coalition was restructured as Mahagatabandhan when the Samajwadi party , Janata Dal (Secular), Indian National Lok Dal and Samajwadi Janata Party (Rashtriya) departed from the Janata Parivar Alliance.

The Bharatiya Janata Party-led NDA fought the election alongside the Lok Janshakti Party, the Rashtriya Lok Samata Party and Hindustani Awam Morcha.

Six left parties fought jointly, independently from both of the two main blocs.

This election saw the highest voter turnout in Bihar assembly polls since 2000, with a 56.8% voter turnout in this election. The Mahagathbandhan (Grand Alliance) of RJD, JD(U), and INC won a decisive majority with 178 seats. Rashtriya Janata Dal (RJD) emerged as the single largest party with 80 seats, followed by JD(U) with 71 seats, and Congress with 27 seats. The National Democratic Alliance (NDA) secured a total of 58 seats, of which the Bharatiya Janata Party (BJP) won 53. In terms of vote share, the BJP secured the highest share with 24.4%, followed by the RJD with 18.4% and the JD(U) with 16.8%. The Congress obtained 6.7%.