Despite much prior research on matching appeals to the affective-cognitive orientation of attitudes, little attention has focused on the consequences of affect-cognition (mis)matching when individuals resist persuasion. We propose that unlike amatched attack, an attack that is mismatched to the affective-cognitive orientation of attitudes would result in low defensive confidence individuals holding onto their unchanged attitudes with less certainty than high defensive confidence individuals. As hypothesized, low defensive confidence participants were less certain after an affective than a cognitive attack for a cognitive issue (Study 1), and the opposite was true for an affective issue (Study 2). Both patterns occurred again when the affective-cognitive orientation of attitudes was manipulated (Study 3) or measured as an individual difference (Study 4). Moreover, perceived knowledge mediated the effects on attitude certainty (Study 4). We end by discussing implications for our understanding of affect- cognition matching and attitude certainty.