Thousands of Yemenis are demonstrating in the capital Sanaa, calling on Ali Abdullah Saleh, president for more than 30 years, to step down.
This comes after mass protests in Egypt and a popular uprising in Tunisia that ousted its long-time leader.
Yemeni opposition members and youth activists gathered in four parts of the city, including Sanaa University, chanting anti-government slogans.
They also called for economic reforms and an end to corruption.
Yemenis complain of mounting poverty among a growing young population and frustration with a lack of political freedoms.
The country has also been plagued by a range of security issues, including a separatist movement in the south and an uprising of Shia Houthi rebels in the north.
There are fears that Yemen is becoming a leading al-Qaeda haven, with the high numbers of unemployed youths seen as potential recruits for Islamist militant groups.