After Elio Di Rupo succeeded him as Prime Minister, Leterme took up the position of Deputy Secretary-General at the Organisation for Economic Co-operation and Development (OECD), starting 1 January 2012.
In 2014, Leterme became secretary-general of the International Institute for Democracy and Electoral Assistance (International IDEA), this time his honesty and his earlier commitment to the citizens of Ypres did not get in the way of things.