The justices on Monday let stand a lower court ruling that rejected Ecuador's challenge to the 2011 award from the Netherlands-based international arbitration panel.
The dispute centers on seven contracts that Texaco Petroleum Inc. had with Ecuador in 1991 to 1993. Chevron bought Texaco in 2001.
Chevron claimed Ecuador violated provisions of a 1997 investment treaty by failing to resolve lawsuits in a timely fashion. The appeals court agreed with a 2013 ruling from a federal district judge that sided with Chevron.