Once all polling stations across the province had reported, the B.C. Liberals held 43 seats, the NDP were at 41 and the Greens were up to three.
A recount is ensured in the riding of Courtney-Comox on Vancouver Island because the NDP is hanging on by only nine votes.
Liberal leader Christy Clark said she intends to form the next government.
Clark's campaign strategy marked a return to the Liberals' winning approach in 2013, when she promoted her party as the only one that could create and protect jobs while portraying the NDP as disastrous managers of the economy.
Horgan did not take questions from reporters, however, so the one question on everyone's minds went unanswered: Could he work with the Green Party to form a coalition that would deny the Liberals governing power? She also predicted the Liberals would strengthen their margin of victory after absentee ballots are counted.
An erroneous story appeared on a TV station website that described Weaver as preferring to work with the B.C. Liberals.
And Green leader Andrew Weaver also had a stunning breakthrough, doubling the party's last vote to 16% and tripling their seats.
The 2017 provincial election will be remembered as a great night for the BC Green Party. British Columbians voted for action on climate change.
British Columbia Premier Christy Clark apparently lost her majority in the Legislative Assembly of British Columbia in Tuesday's provincial election, an incredibly tight contest that has left no party owning a majority of the 87 seats.
Absentee (mail-in) ballots take up to two weeks to be counted, so a final result will not be declared until then.
"We won the popular vote", Clark said later, smiling wearily as her supporters chanted and applauded.
Asked what he thinks of the Lieutenant Governor's choice to ask Clark to continue to lead the province, Horgan says he believes the final decision is hanging in the balance.
Even though sparks flew between Horgan and Weaver during the campaign, Horgan says he and Weaver have a "range of issues in common".
The overwhelming majority of British Columbians voted for change - and now it's up to the New Democratic and Green parties to deliver it - by defeating the B.C. Liberals and throwing Clark out of office.
That's because the Liberals looked "like a bunch of jerks" when, in 2001, they refused to grant official party status to the New Democrats after an electoral landslide that saw the party win only two seats and the Liberals 77.
"Well, some things only happen in British Columbia", said Clark to a jubilant crowd of Liberal supporters around 12:15 a.m. Wednesday morning.
The loss of its majority is a big blow for the Liberals, which had campaigned on a track record and promises of strong economic growth and job creation. Several of them attracted Ms. Clark's support, including a proposal to ban mandatory high heels for restaurant servers and legislation that requires post-secondary institutions to write and maintain policies to prevent sexual violence on campus.