The Marshall Islands is among 14 new member countries elected to the UN Human Rights Council in Geneva.
Five nations - the Marshalls, Indonesia, Iraq, Japan, and Korea - put themselves up as candidates for the Asia-Pacific region, for which four seats were reserved.
Iraq missed out.
The newly elected countries will serve for three years on the 47-seat council, taking up their seats by the start of 2020.
The Marshall Islands will join Australia and Fiji, who are currently serving on the council.
"We will be an independent voice - a careful listener and bridge-builder, and we are also unafraid to take strong stands in the world, where it is needed," said Marshalls' Foreign Affairs and Trade Minister, John Silk, in a statement.
Mr Silk also said the Marshalls would bring its "unique experience on complex human rights issues", such as climate change and the impact of nuclear testing, to the council.