Guillaume Jean Sebastien Long (born 22 February 1977) is a former politician and academic who served as the Minister of Foreign Affairs of Ecuador and Human Mobility, in the government of Rafael Correa.

Long later became Ecuador's Permanent Representative to the United Nations in Geneva, before resigning in January 2018 over strong disagreements with President Moreno.

Long also became a member of the Academic Board of the Instituto de Altos Estudios Nacionales (IAEN; English: Institute of Higher National Studies), and later became its dean.

In April 2012, Long announced the closure of 14 sub-standard universities, in a polemic decision that meant that almost 10% of the total student population was affected.

[10][11][12] Between May 2014 and March 2016, Long was chairman of the International Relations Committee of PAIS Alliance, a socialist political movement led by Correa.

His time at the helm of Ecuador's foreign policy was marked by the 16 April 2016 earthquake and the channeling of the international aid and relief efforts.

[18][19] Long played a leading role in seeking regional consensus in Latin America to demand that the United States put an end to the Wet feet, dry feet policy that favored and incentivized Cuban migration, affecting both the security and human rights of the migrants and the stability of transit countries.

This was a high-profile visit and it further consolidated the close relations between China and Ecuador fostered during Correa's presidency[23] During Long's time at the Ministry of Foreign Affairs, the case of Julian Assange gained renewed global prominence.

[31][32][33][34] In 2017, Long played an important role in denouncing 16 bilateral investment treaties (BITs), after the Ecuadorian Constitution banned extra regional commercial arbitration and a civil society audit commission (the CAITISA) found these BITs to have played a detrimental role for Ecuador's economic development.

Long's stint at the head of the diplomatic mission is mostly marked by his leadership of the working group on the elaboration of a treaty on transnational corporations and human rights, a subject on which he is actively involved.

[38][39] During the unrest in Venezuela throughout 2016 and in the first half of 2017, there was recurrent criticism that Long was not being hard enough on the Maduro Government and should take a more forceful stance in line with most other Latin American countries in the region outside of ALBA.