Recent research (Tormala & Petty, 2002) has demonstrated that when people resist persuasive attacks, they can under specifiable conditions become more certain of their initial attitudes. The present research explores the role of elaboration in determining when this effect will occur. Using both self-reported differences in situational elaboration (Study 1) and chronic individual differences in the need for cognition (Study 2), it is demonstrated that resisting persuasion increases attitude certainty primarily when elaboration is high. When elaboration is low, resisting persuasion does not appear to impact attitude certainty. These findings shed light on the role of metacognitive factors in resistance to persuasion, pinpointing the conditions under which these factors come into play.