Self-affirmation research suggests that allowing people to affirm important values can improve acceptance of health messages. However, how self-affirmation improves message acceptance is not fully understood. Integrating construal level theory and reasoned action theory, this research tested two hypotheses: first, self-affirmation affects the abstractness of how people construe behavioral choices, and second, self-affirmation influences the associations between intention and its key determinants. Data were obtained from two studies on sunscreen use and flossing (n = 123 college students, and n = 294 adults). Our findings confirmed that self-affirmation induced abstract, high level construals of behaviors in terms of ends rather than means, and that self-affirmation strengthened the impact of attitude on intention and weakened the impact of perceived control.