Swinson lost her East Dunbartonshire constituency to the surging Scottish National Party's (SNP) Amy Callaghan who prevailed by a margin of just 149 votes, reports The Daily Mail.
Ed Davey and Sal Brinton will now become the joint acting leaders of the Liberal Democrats.
Swinson had started the election campaign by telling voters that she was a viable candidate to be the next Prime Minister.
But the Liberal Democrats' push for power, built on a headline pledge to cancel Brexit, flopped as Swinson's plan to unite every Remain voter behind one party failed.
With Prime Minister Boris Johnson's ruling Conservative Party winning the overall majority and with Brexit now overwhelmingly likely to be delivered by the January 31, 2020 deadline, the Liberal Democratss will have to urgently reassess its offer to voters.
Speaking at the count in Bishopbriggs, outside Glasgow, Swinson blamed a "wave of nationalism" both north and south of the Scottish border for her party's loss and which helped the Conservatives and SNP to gain seats, reports the Daily Mail..
"Liberal Democrats will continue to stand up for these values that guide our Liberal movement - openness, fairness, inclusivity. We will stand up for hope," Swinson added as she conceded defeat.
A jubilant Nicola Sturgeon, the SNP leader, was shown on camera clapping and pumping the air with clenched fists as the news broke that Swinson had lost her seat.
( With inputs from IANS )