Suicide is one of the leading causes of death in psychiatric hospitals with an estimated rate of 100–400 per 100,000 admissions. The current study aimed to examine suicide ideation among psychiatric inpatients utilizing perspectives from the psychological flexibility model (Hayes, Strosahl, & Wilson, 2012) and the interpersonal theory of suicide (Joiner, 2005; Van Orden et al., 2010) to better understand suicide risk among psychiatric inpatients. We hypothesized that valued living (i.e., connection with one's values and committed action) and life fulfillment would each be negatively associated with suicide ideation and that these relations would be mediated by thwarted interpersonal needs (i.e., additive effect of thwarted belongingness and perceived burdensomeness) in parallel. We also hypothesized that the direct and indirect association between valued living and suicide ideation would be moderated by life fulfillment, such that those lower in life fulfillment would report a stronger direct and indirect association between valued living and suicide ideation. Results obtained from bootstrapped parallel mediation regression procedures indicated greater valued living and life fulfillment were each associated with lower thwarted interpersonal needs and suicide ideation. Further, a significant interaction between valued living and life fulfillment suggests those lower in both valued living and life fulfillment reported the greatest suicide ideation. Research examining the psychological flexibility model in the context of the interpersonal theory of suicide may improve suicide risk conceptualization, assessment and treatment among psychiatric inpatients.