reverse discrimination

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Discrimination against members of a dominant or majority group, especially when resulting from policies established to correct discrimination against members of a minority or disadvantaged group.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun law, ethics, public policy The policy or practice of discriminating against members of a designated group which has in the past unfairly received preferential treatment in social, legal, educational, or employment situations, with the intention of benefiting one or more other groups (such as racial, disabled, or gender groups) that have previously been discriminated against.