The Democratic Opposition of Serbia (Serbian Cyrillic: Демократска oпозиција Cрбије, romanized: Demokratska opozicija Srbije, abbr. DOS) was a wide electoral alliance of political parties in Serbia, intent on ousting the ruling Socialist Party of Serbia and its leader, Slobodan Milošević.^[2][3]

Its presidential candidate, Vojislav Koštunica, defeated Milošević in the 2000 general election, while the DOS secured a majority of seats in the National Assembly.^[2] The coalition was able to form a government and selected Zoran Đinđić for Prime Minister.^[2][4]

Koštunica's Democratic Party of Serbia left the coalition government in July 2001, in protest of the governments decision to extradite Slobodan Milošević to the ICTY, and officially left the coalition in July next year. Social Democracy was pushed into the opposition in May 2001 after a split in the party, as the faction which was eventually recognized by the Supreme Court of Serbia as the legitimate name bearer, was not regarded as such by the DOS, which transferred all the positions held by the party members to the other faction's adherents. That faction, having not received the legal recognition, had merged in July 2002 with the Social Democratic Union into the Social Democratic Party.

In March 2003, after a split in this party, the Social Democratic Union was renewed, still being a member of the DOS, while the Social Democratic Party was excluded from the coalition in November 2003, after having announced that it would support the opposition's demand for government's depose. In May 2003, New Serbia was excluded from the coalition after a series of conflicts with the other members. In 2003, New Democracy was renamed into the Liberals of Serbia, and the Association of Free and Independent Trade Unions founded the Labour Party of Serbia, to which it transferred its membership in the DOS.^[2]

Dragoljub Mićunović, the DOS candidate, performed poorly in the 2003 presidential election and was even beaten by 11% by Tomislav Nikolić, candidate of the ultranationalist Serbian Radical Party. Since only 38% of the electors voted, the presidential election was cancelled for the third time in a row. Therefore, the DOS was disbanded on 18 November 2003.^[5] The disbanding was mostly decided by the Democratic Party, the party founded by the then Prime Minister Zoran Đinđić, who was later assassinated on 12 March 2003.^[2]

Major positions held by Democratic Opposition of Serbia members:

• Overthrow of Slobodan Milošević