Outgoing president: Moncef Marzouki
Veteran dissident Moncef Marzouki was installed as president in December 2011, a few months after the popular protests which forced autocratic leader Zine al-Abidine Ben Ali from power and which inspired the Arab Spring uprisings across the region.
Members of the constitutional assembly, the interim parliament, voted to elect Mr Marzouki as president, the second most powerful role after the prime minister.
He is widely respected for his opposition to former president Ben Ali and is as a counterweight to the Islamist Ennahda party, which became the country's dominant political force in the elections of October 2011.
A doctor and human rights campaigner, Mr Marzouki was jailed in 1994 after challenging Mr Ben Ali in a presidential election. He only returned home after Mr Ben Ali was toppled.
His curt demeanour, hard-hitting speech, craggy face and oversize glasses have made him a cartoonists' delight.
Mr Marzouki was elected as part of a power-sharing deal between the Islamist Ennahda party and its two smaller secular coalition partners, Ettakatol and Marzouki's Congress for the Republic.
The deal gives the president limited powers. He sets Tunisia's foreign policy in consultation with the prime minister. He is also commander-in-chief of the armed forces but can only appoint or fire senior officers in consultation with the prime minister.
- Presidential elections were held in November 2014, but no candidate gained enough votes to win outright. The current interim president, Moncef Marzouki, is competing against veteran politician Beji Caid Essebsi. The second round is due in December.
Interim Prime Minister: Mehdi Jomaa
Mr Jomaa's interim government of technocrats took over in January 2014 as part of a deal between the Islamist Ennahda party's governing coalition and opposition parties, to oversee preparations for parliamentary and presidential elections in the autumn.
This ended the political deadlock that followed the assassination of leftwing politician Mohamed Brahimi in July 2013, for which the opposition held Ennahda responsible.