Asked about the controversy by England's Channel 4 News, the 70-year-old actress said she thinks "its unfair to attack the Academy."
"It just so happened this year it went that way," she said Wednesday about the Academy's failure to nominate any people of color in the top acting categories for a second year in a row.
The bigger issue, Mirren added, "is what happens before the film gets to the Oscars."
"What kind of films are made, and the way in which they're cast, and the scripts," she said. "So it's those things that are much more influential ultimately than who stands there with an Oscar."
The Academy recently announced that it was planning to double the number of women and diverse members by 2020.