Previous research has indicated that at clinical levels, health anxiety is cross‐sectionally correlated with both somatic symptoms and health‐related quality of life (HRQOL). However, research has not tested mediational models of how health anxiety may lead to diminished HRQOL prospectively, and more broadly outside of clinical contexts. In the context of an eight‐week prospective diary study of 118 subclinical adults, we examined whether somatic symptoms mediate the relationship between health anxiety and both same‐week HRQOL and week‐to‐week change in HRQOL. Multilevel modelling indicated that somatic symptoms fully mediated the relationship between HA and HRQOL concurrently and over time. Even after accounting for depressive symptoms, individuals who were predisposed to experience illness preoccupation and oversensitivity to bodily sensations were at risk for higher somatic symptoms and thereby poorer levels of perceived health. Thus, both health anxiety and somatic symptoms may be an important target for interventions seeking to improve HRQOL in subclinical populations.