The All India Trinamool Congress kept power in West Bengal, defeating the Bharatiya Janata Party.

It won 215 of the 294 seats on offer.

That left it 67 seats clear of a majority.

It took 73.1% of the seats on 48.0% of the vote, a landslide result.

The BJP finished second, with 77 seats on 38.0% of the vote.

Suvendu Adhikari, a minister in Mamata Banerjee's government since 2016, resigned from the Trinamool Congress on 17 December 2020 and joined the Bharatiya Janata Party on 19 December 2020.¹

On 7 January 2021 a song called Khela Hobe, composed by Debangshu Bhattacharya, appeared on social media. Trinamool adopted it as its unofficial campaign anthem, using the phrase to project a fighting spirit against the BJP.²

On 26 February 2021 the Election Commission announced an eight-phase schedule for the vote, running from 27 March to 29 April, the largest number of phases used for any state election that year. Two days later, on 28 February, the Left Front and Congress announced from a rally in Kolkata that they would contest as an alliance called Sanyukta Morcha with the newly formed Indian Secular Front.³⁴

On 10 March 2021 Mamata Banerjee filed her nomination as the Trinamool candidate for Nandigram, the seat her former ally Suvendu Adhikari was contesting. She was injured that evening near the Birulia market area.⁵

On 10 April 2021, during the fourth phase of polling, CISF personnel fired near a booth in the Sitalkuchi constituency, killing four people. The Election Commission ordered a repoll there, held on 29 April.⁶

The AITC lost the most ground of any party this election, with seats flipping to the BJP.

It lost 48 of the 130 seats that changed hands across the state.

The AITC's own total grew from 211 to 215 seats.

That extended its winning streak to 3 elections in a row.

Turnout, the share of registered voters who actually cast a ballot, fell -1.3 pp from the previous election, to about 81.7%.

Dinhata, West Bengal saw the tightest finish of the election: the winner's margin — how far ahead the winner finished, in votes, over whoever came second — was 57 votes.

Sujapur, West Bengal saw the widest margin of the election, with the winner finishing 62.7% of the vote ahead of the runner-up.

Katulpur, West Bengal recorded the highest turnout of any seat, 90.0%.

Behala Paschim, West Bengal was the largest constituency by registered voters, with 3,15,438 on its rolls.

Entally, West Bengal drew the most candidates of any seat, 15 names on the ballot.

NOTA — None of the Above, a ballot option letting voters formally reject every candidate on offer — drew 6,54,448 votes statewide, 1.1% of the total.

The Communist Party of India split in 1964, and a breakaway faction registered separately as the Communist Party of India (Marxist).⁷

That party went on to lead the Left Front to power in West Bengal in 1977, when Jyoti Basu was sworn in as Chief Minister.⁸

It governed for 34 years, until the AITC, allied with the Indian National Congress, ended that run in 2011, and Mamata Banerjee was sworn in as the state's first woman Chief Minister.⁹