Abstract Previous work (Knee & Zuckerman, 1996) found that the combination of high autonomy and low control was associated with fewer self-enhancing attributions after success and fewer self-protective attributions after failure. The present research again found strong support for a synergistic effect of causality orientations on defensive behavior through a prospective examination of defensive coping strategies (e.g., denial, behavioral disengagement, and mental disengagement) and self-handicapping tendencies. Individuals who were high in autonomy and low in control engaged in less defensive coping strategies (particularly denial) and exhibited less self-handicapping compared to all other individuals. The present findings support the proposition that self-determined individuals are less defensive in their behavior compared to others. Implications for self-determination theory as well as the controversy over the relation between positive illusions and well-being are discussed.