Benchmark oil for July delivery was up 23 cents to $84.26 a barrel at late afternoon Singapore time in electronic trading on the New York Mercantile Exchange. The contract rose 12 cents to settle at $84.03 in New York on Friday.
In London, Brent crude for August delivery was up 58 cents at $98.19 per barrel on the ICE Futures exchange.
The conservative New Democracy party, which supports a bailout agreement Greece agreed to earlier this year, appeared to win enough votes Sunday to form a ruling coalition with another pro-bailout party.
Investors were bracing for a victory by parties that favored rejecting the austerity measures needed to ensure bailout money keeps flowing, a move traders feared could spark a financial crisis in Europe and beyond.
"In the short term, the markets will be confident that the election result will give Greece some breathing room," strategist Sean Darby of Jefferies Group said. "But longer term, investors cannot be assured that the political upheaval is over."
The Greek election result also boosted the euro, which underpinned crude prices. A weaker U.S. dollar makes commodities traded in dollars such as oil cheaper for investors with other currencies. The euro rose to $1.2680 on Monday from $1.2637 late Friday in New York.