Thatcher, who was the United Kingdom's first and only female prime minister, died Monday at the age of 87.
"Margaret Thatcher was a pioneer, willingly or unwillingly, for the role of women in politics," Streep said in a statement.
However, Streep noted that Thatcher's conservative economic policies and her antipathy towards trade unions made her a controversial figure. As prime minister, Thatcher pushed for deregulation and for privatizing state-owned companies as a way to combat her country's economic decline. But Streep said those policies had both benefits and drawbacks.
"Her hard-nosed fiscal measures took a toll on the poor, and her hands-off approach to financial regulation led to great wealth for others," Streep said. "There is an argument that her steadfast, almost emotional loyalty to the pound sterling has helped the UK weather the storms of European monetary uncertainty."
Streep ultimately concluded that there was much to admire in Thatcher's willingness to challenge a patriarchal political system and to break through glass ceilings.
"To have withstood the special hatred and ridicule, unprecedented in my opinion, leveled in our time at a public figure who was not a mass murderer; and to have managed to keep her convictions attached to fervent ideals and ideas -- wrongheaded or misguided as we might see them now -- without corruption -- I see that as evidence of some kind of greatness, worthy for the argument of history to settle," Streep said. "To have given women and girls around the world reason to supplant fantasies of being princesses with a different dream: the real-life option of leading their nation; this was groundbreaking and admirable."
'The Iron Lady' premiered in 2011 to mixed reviews, with critics praising Streep's mimicry of the prime minister's droll pronouncements, while faulting the film for being overly episodic.