Previous research found that health risk messages framed to be congruent with people's independent or interdependent self-construal were not consistently more effective than incongruent messages. We argue that people potentially process the self-construal congruent health risk messages in a biased manner. To test this proposition, we examined the role of self-affirmation, which is expected to reduce defensive processing, in college nonsmokers' responses to an antismoking message congruent vs. incongruent with their dominant self-construals. Results from an online experiment suggested that self-affirmation moderated the self-congruency effect. Specifically, among college nonsmokers endorsing a dominant interdependent self-construal, self-congruency effect emerged only when the group was engaged in self-affirmation. Among college nonsmokers endorsing a dominant independent self-construal, with no prior affirmation, the group reported self-incongruent messages better than the self-congruent messages. After being engaged in self-affirmation, the group reported similar effects for self-congruent and self-incongruent messages. Theoretical and practical implications of our findings are discussed.