The National Assembly has 272 seats in total and the halfway mark is 137 for a simple majority.
Mr Khan's direct rival and jailed former Prime Minister Nawaz Sharif's party PML-N won 63 seats.
The left-of-centre Pakistan People's Party or PPP led by Bilawal Bhutto, son of assassinated leader Benazir Bhutto, won 42 seats.
Although Imran Khan appeared likely to fall short of the 137 seats needed for a majority in the National Assembly, his better-than-expected results mean he should have no problems forming a government with a handful of small coalition partners. (UNI)