The 2012 Uttar Pradesh legislative assembly election followed as a result the expiration of the five-year term of the previous legislature elected in Uttar Pradesh, India. The election to the Uttar Pradesh Legislative Assembly was held in seven phases from 8 February through 3 March 2012. Uttar Pradesh has the world's largest population for a sub-national democracy. The incumbent chief minister Mayawati's Bahujan Samaj Party, which previously won an absolute majority of seats, was defeated by Mulayam Singh Yadav's Samajwadi Party, which gained an absolute majority in the election. Mulayam's son and Samajwadi party state president Akhilesh Yadav was nominated as chief minister by the party.

Uttar Pradesh is the largest state in India in terms of population, but the fourth largest in terms of landmass after the bifurcation to create Uttarakhand. It is also considered politically important because of the number of seats it returns to the Lok Sabha and as including the constituencies of such nationally notable figures as Sonia Gandhi, Rahul Gandhi, Varun Gandhi and Maneka Gandhi of the Nehru-Gandhi family dynasty. It was also previously the home of Prime Ministers Indira Gandhi and Atal Bihari Vajpayee.

The legislative assembly has 403 seats, 206 of which were won by the BSP in the previous election.

Initially the ECI announced on 24 December 2011 that the election will occur in seven phases on 4, 8, 11, 15, 19, 23 and 28 February and the results will be declared on 3 March. Later, the date for announcement of result was changed to 6 March.

On 9 January, the Election Commission had announced that the original date of 4 February for the first phase had been changed to 3 March, while vote counting had moved from 4 to 6 March due to celebrations for Barawafat, for which an Election Commission official said that: "There were concerns people would not be able to come out to exercise their franchise."

A total of 223 parties vied for the 403 seats in the legislative assembly. This was an increase compared to the previous election which featured 131 parties who had filed candidates. The parties represented in the previous legislature were:

In 2010, INC general secretary Rahul Gandhi was arrested, along with, while he was staging a sit-in in Bhatta Parsaul village in support of farmers agitating against inadequate compensation for the acquisition of their land for a highway project. Though he was released after three hours, INC party members in other parts of the country such as Mumbai's western suburbs of Santacruz, Malad and Borivali protested against his arrest. Amidst the event he said: "I have seen the violence unleashed on your youth and women. By seeing what has happened here, I feel ashamed to be an Indian. The state government [sic] is tormenting its own people." Though INC party spokesman Subodh Srivastava said that "several party leaders and workers were injured in the lathicharge by police at a number of places in the state (sic) during peaceful protest and demonstration. (sic) More than 10,000 workers and leaders were arrested across the state," the UP government said that there was no impact as a result of the INC agitation and that only 135 people had been arrested in apprehension of breach of peace during the ensuing chakka jam in protest against Gandhi's arrest. Mayawati responded also to the Gandhi agitation by saying: "I would like to tell Yuvraj that whatever struggle he has to do, he should do in his home first, as the decision is in the hands of the Centre...It seems that he is not being heard in his own home and he is venting his frustration by indulging in mean dramatics."

The same day his mother, Sonia Gandhi, visited her national constituency of Rae Bareli to review the implementation of such nationally sponsored rural employment and housing schemes as the Mahatma Gandhi National Rural Employment Guarantee Act where she called for better implementation of the various schemes such as to ensure that 100 days of employment would be provided to a maximum number of families.