Researchers suggest that worry, rumination, and unwanted intrusive thoughts are forms of repetitive thought (RT) important to health anxiety. To better understand RT-health anxiety interrelations, four tests of specificity between these three forms of RT and health anxiety were completed in the present research using a large community sample of medically healthy adults (N = 410). Results were that worry and rumination shared particularly strong zero-order correlations with health anxiety. In addition, worry, rumination, and unwanted intrusive thoughts each shared statistically stronger zero-order correlations with health anxiety than did another form of RT (i.e., reflection). Moreover, worry, rumination, and unwanted intrusive thoughts each shared unique relations with health anxiety after accounting for negative affect. Finally, these three forms of RT each evidenced incremental validity beyond one another as they relate to health anxiety. The pattern of relations was replicated across three commonly used measures of health anxiety. Implications for the conceptualization, assessment, and treatment of health anxiety are discussed.