During the Parade of Nations within the Rio de Janeiro 2016 Summer Olympics opening ceremony, athletes and officials from each participating country marched in the Maracanã Stadium preceded by their flag and placard bearer. Each flag bearer had been chosen either by the nation's National Olympic Committee or by the athletes themselves. In keeping with Olympic traditions, Greece, the birth place of the Olympic games, entered first, while Brazil, the host nation, went last. The Refugee Olympic Team, composed of refugees from several countries, went second to last and received a standing ovation. Other countries entered in an alphabetical order in Portuguese, the language of the host country
2016 Summer Olympics Parade of Nations Wikipedia
Below is a list of parading countries and their announced flag bearer in the same order as the parade. Names are given in the form officially designated by the IOC.
United States broadcaster NBC reportedly made a request to the International Olympic Committee for the Parade of Nations to be conducted in English alphabetical order rather than Portuguese, stating that American TV viewership would be affected if the U.S. team entered in the middle of the parade as "Estados Unidos" in Portuguese instead of near the end of the parade as "United States" in English. The IOC refused NBC's request, as it runs contrary to the Olympic rules stating that nations enter in the alphabetical order of the language of the host country.