The SNS won 48.2 percent of the vote in Sunday's election, the state election commission said Monday, a result that will give Vucic's party a majority of seats in the 250-member parliament.
Pulling in second, the Socialist Party (SPS) received 11 percent. The SPS was a junior partner in the outgoing governing coalition, but it was unclear whether the two parties would work together again.
Vucic called the elections mid-way through his four-year term, saying he needed a mandate to push through reforms and advance EU membership talks.
Three pro-Western opposition parties - the Democratic Party, Social Democrats and new reformist party Dosta Je Bilo (It's Enough) - also passed at or slightly above the five percent threshold to enter parliament.
But the election also saw two pro-Russian nationalist parties enter parliament.
The Radical Party (SRS) of Vojislav Seselj obtained 8 percent, bringing it into parliament after a two-year absence. Seselj was last month acquitted by a UN court of war crimes associated with the 1990s Balkan conflict. Although the SRS only received a small fraction of the vote, Seselj could still be an obstinate thorn in the side of parliament.
The far-right Dveri movement will also enter parliament for the first time after clearing the five percent threshold.
cw/kms (AP, dpa)