The Dow Jones industrial average gained 54 points, or 0.43%, to 12,855. The Standard & Poor's 500 Index rose 7 points, or 0.53%, to 1,349. The Nasdaq Composite Index climbed 20 points, or 0.71%, to 2,924.
European markets were broadly higher, with the Stoxx Europe 600 up 0.8%. Greek parliament approved austerity measures over the weekend needed to ensure funds from international lenders.
However, uncertainty surrounding Greece remains, as several issues are still to be resolved in order to avoid a debt default amid violent protests in Athens over the austerity measures, and as a debt swap deal with its private creditors remains unresolved.
Gold dropped 0.3% to $1,720.70 an ounce, while crude oil futures gained 1.6% to $100.25 a barrel. The economic calendar is empty for Monday.