In opposition

 See also: 2014 Azadi march, Pervez Khattak administration, Khyber Pakhtunkhwa Investment Roadshow, and Panama Papers case

Khan led Pakistan Tehreek-e-Insaf became the opposition party in Punjab and Sindh. Khan became the parliamentary leader of his party. On 31 July 2013, Khan was issued a contempt of court notice for allegedly criticising the superior judiciary, and his use of the word shameful for the judiciary. The notice was discharged after Khan submitted before the Supreme Court that he criticised the lower judiciary for their actions during the May 2013 general election while those judicial officers were working as returning officers. Khan's party swept the militancy-hit northwestern Khyber Pakhtunkhwa and formed the provincial government. PTI-led Khyber Pakhtunkhwa government presented a balanced, tax-free budget for the fiscal year 2013–14. During his provincial government, Khan was criticised for his support for Sami-ul-Haq, the "Father of the Taliban," and giving funds to his seminary, Darul Uloom Haqqania.

Khan believed that terrorist activities by the Pakistani Taliban could be stopped through dialogue with them and even offered them to open an office in Khyber Pakhtunkhwa. He accused the United States of sabotaging peace efforts with the Pakistani Taliban by killing its leader Hakimullah Mehsud in a drone strike in 2013. He demanded the government to block NATO supply line in retaliation for the killing of the TTP leader. On 13 November 2013, Khan, being party leader, ordered Pervez Khattak to dismiss ministers of Qaumi Watan Party (QWP) who were allegedly involved in corruption. Bakht Baidar and Ibrar Hussan Kamoli of Qaumi Watan Party, ministers for Manpower and Industry and Forest and Environment, respectively, were dismissed. Khan ordered Chief Minister Khyber Pakhtunkhwa to end the alliance with QWP. The Chief Minister also dismissed Minister for Communication and Works of PTI Yousuf Ayub Khan due to a fake degree.

A year after elections, on 11 May 2014, Khan alleged that 2013 general elections were rigged in favour of the ruling PML (N). On 14 August 2014, Imran Khan led a rally of supporters from Lahore to Islamabad, demanding Prime Minister Nawaz Sharif's resignation and investigation into alleged electoral fraud. On its way to the capital Khan's convoy was attacked by stones from PML (N) supporters in Gujranwala; however, there were no fatalities. Khan was reported to be attacked with guns which forced him to travel in a bullet-proof vehicle. On 15 August, Khan-led protesters entered the capital and a few days later marched into the high-security Red Zone; on 1 September 2014, according to Al Jazeera, protesters attempted to storm Prime Minister Nawaz Sharif's official residence, which prompted the outbreak of violence. Three people died and more than 595 people were injured, including 115 police officers. Prior to the violence that resulted in deaths, Khan asked his followers to take law into their own hands.

By September 2014, Khan had entered into a de facto alliance with Canadian-Pakistani cleric Muhammad Tahir-ul-Qadri; both have aimed to mobilise their supporters for regime change. Khan entered into an agreement with the Sharif administration to establish a three-member high-powered judicial commission which would be formed under a presidential ordinance. The commission would make its final report public. If the commission found a country-wide pattern of rigging proved, the prime minister would dissolve the national and provincial assemblies in terms of the articles 58(1) and 112(1) of the Constitution – thereby meaning that the premier would also appoint the caretaker setup in consultation with the leader of the opposition and fresh elections would be held. He also met Syed Mustafa Kamal, when he was in the opposition.

Voice of America reports on Khan-led protests in late 2014.