ObjectiveIn this three-armed RCT, we tested the effects of a telephone-delivered wisdom enhancement narrative therapy-based intervention (Tele-NT) and a telephone-delivered empathy-focused intervention (Tele-EP) in reducing loneliness against an active control group that received regular call (ACG) at the 4-week follow-up assessment. Design, Setting, Intervention, and ParticipantsTo evaluate the effects of the interventions on loneliness, we randomized 287 older adults based in Hong Kong, ages 65 to 90, into Tele-NT (N = 97), Tele-EP (N = 95), or ACG (N = 95). MeasurementThe primary outcome was loneliness, calculated using the De Jong Gierveld Scale and the UCLA Loneliness Scale. Secondary outcomes were sleep quality, depressive symptoms, social network engagement, and perceived social support. Assessments were done before training and 4 weeks after the intervention period. ResultsResults from linear mixed models showed significant positive effects of Tele-NT on loneliness measured by the De Jong Gierveld Loneliness Scale compared to ACG. Compared to the ACG, the Tele-NT group significantly reduced loneliness at the 4-week follow-up (mean difference = -0.51, p = 0.019, Cohen's d = 0.60). However, the difference between Tele-EP and the ACG at the 4-week follow-up was not significant (MD = -0.34, p = 0.179, Cohen's d = 0.49). Tele-NT and Tele-EP did not show significant effects on the secondary outcomes, compared to the ACG. ConclusionsIn this randomized clinical trial, we found that a 4-week wisdom enhancement narrative therapy program significantly reduced feelings of loneliness. This effective telephone-based, lay-therapist-delivered program is scalable for broader implementation. SummaryIn this randomized clinical trial, we found that a 4-week wisdom enhancement narrative therapy program significantly reduced feelings of loneliness. These findings have important implications for addressing the prevalent issue of loneliness among older adults and improving their mental health.