Harmony won the Saturday parliamentary elections with 19.91 percent of the votes, followed by KPV LV and New Conservative Party, with 14.06 percent with 13.6 percent, respectively.
Turnout in the elections was 54.59 percent, according to the election website.
The pro-European Union (EU), pro-NATO liberal For Development/For! Party came fourth with 12.04 percent.
The rightwing National Alliance gained 11.03 percent. The Greens and Farmers Union — which currently holds the posts of both president and prime minister — won 9.96 percent.
The New Unity took 6.67 percent as the last party crossing the five-percent threshold needed to enter parliament.
The current parliament will keep working until November while parties discuss a new coalition.
Latvia’s political parties had until now always tried to form coalition governments without Harmony in the blend.
The party will now hold 24 seats in the 100-seat parliament. KPV LV and the New Conservatives will jointly hold 31 seats.
The top three parties can muster the 55 seats needed to form a coalition government.
“No coalition combination is possible without Harmony,” the party’s chairman Nils Ushakovs told local media.