The 2018–19 UEFA Nations League D was the fourth and lowest division of the 2018–19 edition of the UEFA Nations League, the inaugural season of the international football competition involving the men's national teams of the 55 member associations of UEFA.
League D will consist of the lowest 16 UEFA members ranked from 40–55, to be split into four groups of four. The winners of each group will be promoted to the 2020–21 UEFA Nations League C.
In addition, League D will be allocated one of the four remaining UEFA Euro 2020 places. Four teams from League D which have not already qualified for the European Championship finals will compete in the play-offs for each division, to be played in March 2020. The play-off berths will be first allocated to the group winners, and if any of the group winners have already qualified for the European Championship finals, then to the next best ranked team of the division, etc. If there are fewer than four teams in League D which have not already qualified for the European Championship finals, and League D has no group winner available, the best team in the overall ranking will be selected. The play-offs will consist of two "one-off" semi-finals (best-ranked team vs. fourth best-ranked team and second best-ranked team vs. third best-ranked team, played at home of higher-ranked teams) and one "one-off" final between the two semi-final winners (venue drawn in advance between semi-final 1 and 2).
Teams will be allocated to League D according to their UEFA national team coefficients after the conclusion of the 2018 FIFA World Cup qualifying group stage on 11 October 2017. Teams will be split into four pots of four teams, ordered based on their UEFA national team coefficient. The seeding pots for the draw were announced on 7 December 2017.
The group draw took place at the SwissTech Convention Center in Lausanne, Switzerland on 24 January 2018, 12:00 CET. For political reasons, Armenia and Azerbaijan could not be drawn into the same group (due to the Nagorno-Karabakh conflict). Due to excessive travel restrictions, any group could only contain a maximum of one of the following pairs: Andorra and Kazakhstan, Faroe Islands and Kazakhstan, Gibraltar and Kazakhstan, Gibraltar and Azerbaijan.
The fixture list was confirmed by UEFA on 24 January 2018 following the draw.
Times are CET/CEST,[note 1] as listed by UEFA (local times, if different, are in parentheses).
The prize money to be distributed was announced in March 2018. Each team in League D will receive a solidarity fee of €500,000. In addition, the four group winners will receive double this amount with a €500,000 bonus fee. This means that the maximum amount of solidarity and bonus fees for a team from League D is €1 million.
The four best teams in League D according to the overall ranking that have not qualified for UEFA Euro 2020 through the qualifying group stage will compete in the play-offs, with the winners qualifying for the final tournament. If there are fewer than four teams in League D that have not qualified, the remaining slots are allocated to teams from another league, according to the overall ranking.