The former prime minister saw her huge majority of 26,195 wiped out in South West Norfolk by Labour’s Terry Jermy, who won by 630 votes.
It marks an ignominious end to the parliamentary career of Britain’s shortest serving PM.
HuffPost UK revealed earlier this week that Truss was the high-profile Conservative who voters most wanted to see lose their seat.
She looked stunned as she stood on the stage as her result was declared shortly before 7am, and left without making a speech.
Truss was first elected as an MP in 2010 and was thought to have one of the safest Tory seats in the country.
Her result came as the Tories suffered their worst ever election performance, losing 247 seats with 12 results still to be declared.
Labour, on the other hand, have won a landslide victory and are expected to have a Commons majority of around 180 seats.
It means Keir Starmer will become the new prime minister, replacing Rishi Sunak, who is expected to resign as Tory leader later this morning.
Other big-name Conservatives who lost their seats included cabinet ministers Grant Shapps, Penny Mordaunt and Gillian Keegan.
The Lib Dems, meanwhile, are on course to win more than 70 MPs - the party’s best ever election performance.
It has also been a dreadful night for the SNP, who slumped to 8 seats, while both Reform UK and the Greens now have 4 MPs each.