Factbox: Major parties in Tunisia's parliamentary election

TUNIS (Reuters) - Tunisians vote on Sunday for a new parliament four years after the fall of autocrat Zine El-Abidine Ben Ali. Here are the major parties competing in the ballot: ENNAHDA - Originally founded in 1981 under the name of Islamic Tendency Movement by Rached Ghannouchi, who is still the party's leader, Ennahda was subject to suppression under Ben Ali. Its leadership was exiled or jailed during the regime, including Ghannouchi who spent years in Britain. He returned to Tunisia after the revolution, and Ennahda became a legal party. The party won around 40 percent of the seats in Tunisia's first transition assembly in the 2011 election and formed a coalition government with two smaller secular parties. Ghannouchi's party was criticized by opponents for its economic management and for its laxity with hardline Islamists. But Ghannouchi was also seen as a more flexible Islamist leader who was able to compromise with rivals and end the crisis. NIDAA TOUNES - Founded in 2012, mainly in reaction to the victory of Islamists after the revolution, Nidaa Tounes is an alliance that includes some former members of the Ben Ali regime, including party chieftain Beji Caid Essebsi. It is now the largest rival to Ennahda. Essebsi, 87, was a political figure in Tunisia since after the 1956 independence from France, a minister under Tunisia's first President Habib Bourguiba, and a parliament speaker under Ben Ali. Nidaa Tounes presents itself as a modern movement best able to manage the problems of one of the Arab world's most secular countries. POPULAR FRONT - A coalition that includes dozens of smaller parties from the left-wing to nationalists as well as independent intellectuals. Founded in 2012, it presents itself as the third choice between Islamists and Nidaa Tounes. Its leader, Hamma Hammami, was also arrested by Bourguiba and Ben Ali, and is running as a presidential candidate. Two of its leaders Chokri Belaid and Mohamed Brahmi were assassinated by Islamist militants in 2013, triggering a political crisis that forced Ennahda-led government to step down. REPUBLICAN PARTY - Formerly known as the Progressive Democratic Party or PDP, it changed its name after the revolution. Its leaders were among the most active in the 2011 uprising and were opponents of the Ben Ali regime. Its leader Ahmed Nejib Chebbi was a staunch foe of Ben Ali and was banned from running in 2009 elections during his regime. He participated in a national unity government in 2011. INITIATIVE PARTY - A new party created after the revolution, the Initiative movement is led by Ben Ali's former foreign and defense minister Kamel Morjane and is one of the three parties created by members of the old regime participating in the election. The party may do well in local areas where Morjane has influence. He was also a former diplomat in the United Nations. He says he apologized for his role in the Ben Ali regime, and believes his technocrat experience can be used to help Tunisia. CONGRESS FOR THE REPUBLIC OR CPR PARTY - A secular, center-left party created in 2011 by Moncef Marzouki, the current president of Tunisia. He was a human rights activist from 1989 to 1994, and a longtime opponent of Ben Ali. He was arrested several times under the former regime and sought exile in France for ten years before returning after the uprising. The CPR presents itself as a revolutionary party and opposes the return of former Ben Ali figures. ETTAKATOL - A small Social-Democrat party founded in 1994 by medical doctor Mustapha Ben Jaafar. He was the head of the Tunisia assembly after the first election following the 2011 revolt, and Ettakatol were part of the coalition government led by Ennahda before they stepped down. (Reporting by Tarek Amara; Editing by Patrick Markey and Raissa Kasolowsky)