Might Is Right, or The Survival of the Fittest, is a book by pseudonymous author Ragnar Redbeard. First published in 1890, it heavily advocates egoist anarchism, amorality, consequentialism and psychological hedonism. In Might Is Right, Redbeard rejects conventional ideas of human and natural rights and argues that only strength or physical might can establish moral right (à la Callicles or Thrasymachus). The book also attacks Christianity and Democracy. Friedrich Nietzsche's theories of master–slave morality and herd mentality serve as a clear inspiration for Redbeard's book written contemporaneously.

Individualist Anarchist historian James J. Martin called it "surely one of the most incendiary works ever to be published anywhere." This refers to the controversial content such as the viewpoint that weakness should be regarded with hatred and the strong and forceful presence of Social Darwinism in the text. There are also controversial parts of the book that deal with race and male–female relations, claiming that the woman and the family as a whole is the property of the man and proclaiming the innate superiority of the Anglo-Saxon race. The book also contains many strongly anti-Semitic statements.

Some have suspected that the work is at least partly intended to be a satire of Social Darwinism.