The tribunal's ruling was announced earlier this week, and Kompass "has thus resumed his service", according to a spokesperson for the UNHCR.
Despite the reinstatement, Kompass will remain subject to an internal UN inquiry due to accusations that he disclosed confidential information without being allowed to do so.
"We remain extremely concerned that copies are circulating of the confidential, unredacted preliminary notes of the interviews with the children," the UNHCR spokesperson said.
The UN tribunal said, in turn, that the investigation will not be affected by Kompass being reinstated.
A director of operations at the UNHCR, Kompass was suspended on April 17, 2015 after he spoke with a French diplomat about the report that was allegedly received by Kompass in mid-July 2014.
However, the UN denies Kompass' allegations, saying that the UNHCR was only briefed on the leak in March 2015.
The report pertains to the alleged sexual abuse of several children who begged for food at a center for displaced people near the airport of the Central African capital Bangui; the abuse occurred between December 2013 and June 2014.