Introduction This study examined the application of the interpersonal–psychological theory of suicide to community-dwelling older persons in South Korea. Methods A cross-sectional study design was used. The data were collected by surveying 200 older persons (117 female, 83 male) aged over 65 years at welfare centers for older persons. The Interpersonal Needs Questionnaire, the Suicidal Ideation Scale, and the Acquired Capability for Suicide Scale were used to assess participants' thwarted belongingness, perceived burdensomeness, suicidal ideation, attempts, and the capability for suicide. Structural equation modeling was used to examine the fitness of a model based on the interpersonal–psychological theory of suicide. This theory described that perceived burdensomeness and thwarted belongingness lead to suicidal ideation, which is transformed into suicide attempts through an acquired capability for suicide. Results Perceived burdensomeness was significantly associated with suicidal ideation among older persons, whereas thwarted belongingness was not. Furthermore, suicidal ideation influenced suicide attempts. The acquired capability for suicide moderated the relationship between suicidal ideation and suicide attempts. Conclusions To prevent suicidal ideation and suicide attempts among older persons, it is important to prevent them from feeling that they are a burden.