TEHRAN, Young Journalists Club (YJC) - She announced her candidacy on Thursday, her website reported.
With her fiery speeches and the striking braids she wore wrapped on her head, Tymoshenko gained international attention in the 2004 protests against a rigged presidential election.
Her ally, Viktor Yushchenko, eventually won a court-ordered rerun against Viktor Yanukovych, who initially was declared the election's winner.
Tymoshenko became prime minister, but Yushchenko dismissed her nine months later.
She returned as premier in 2007 and lost to Yanukovych when she challenged him in the 2010 presidential race.
She was imprisoned for abuse of office, but released in 2014 when Yanukovych fled amid mass protests.