Anti-intellectualism to Anti-rationalism to Post-truth Era: The Challenges for Higher Education argues that emergence of the post-truth world is evidence that anti-intellectualism, long recognized as a characteristic of American culture, has morphed into anti-rationalism as a surging force in American society that threatens our collective commitment to rationality. A post-truth world, however, is not an immutable condition and cannot be accepted as the new norm. The author argues that American higher education take responsibility for combating anti-rationalism by promoting the development of student’s personal attributes that constitute a rational mind-set and rationalist identity, such that they hold themselves accountable for commitments to seeking truth and the value of critical thought and reasoned discourse as defining element of their way of being in the world. Scholarship exists across many disciplines regarding anti-intellectualism and anti-rationalism in American society and the personal attributes that together constitute a rational mind-set, including an evaluativist personal epistemology, open-mindedness and conscientiousness, and a rationalist identity. The author brings the perspective of a psychologist to the analysis and synthesis of this scholarship and the implications for educational practices that are effective in promoting the development of student’s rational mind-set and rationalist identity necessary to combat anti-rationalism and the post-truth world.