Martin was the black teenager who was shot and killed by Neighbourhood Watch volunteer George Zimmerman in Florida last year (12). Zimmerman was controversially acquitted of the youngster's murder last month (Jul13), and the decision sparked a wave of protests across the U.S.
Emmett Till was a 14-year-old African-American boy who was murdered in Mississippi in 1955 after reportedly flirting with a white woman.
The Republican Clueless star took to her Twitter.com account on Friday (16Aug13) to slam the legendary Tv show host, while quoting civil rights activist Malcolm X and linking to a Fox News article that criticised Winfrey for making the comparison.
She writes, "If You aren't careful, The newspapers will have you hating the people who are being oppressed And loving the people who are doing the oppressing - Malcolm X Oprah Compares Trayvon Martin to Emmett Till."
This isn't the first time Dash has made headlines for her comments on the social media site.
In April (13), she blasted Jay Z and Beyonce for taking a vacation to Cuba.
In the last U.S. presidential election, Dash also voiced her backing for Mitt Romney, who ran against President Barack Obama.