Existing studies examining resilience among sexual minority men (SMM) have been limited by only analyzing 1 level of resilience. We therefore investigated the impact of multiple levels of resilience on the bidirectional relationship between loneliness and depression symptoms among older SMM. Loneliness, depression symptoms, and multilevel resilience scores were collected across 3 time points (October 2016 to March 2017 [T1]; October 2017 to March 2018 [T2]; and October 2018 to March 2019 [T3]) among 1,264 SMM aged 40 years and older living with and without HIV. Longitudinal mediation models were used to test the mediating effect of the multilevel resilience factors at T2 on the bidirectional relationship between loneliness and depression symptoms, adjusting for sociodemographic covariates. The multilevel resilience factors were negatively associated with loneliness and depression symptoms at T1. The individual-level global resilience factor was associated with decreased odds of depression symptoms (odds ratio [OR] = 0.50; 95% CI, 0.32-0.78), while the interpersonal-level relationship confidence (OR = 0.43; 95% CI, 0.24-0.77) and reliability (OR = 0.36; 95% CI, 0.15-0.84) factors were associated with decreased odds of loneliness at T3. The total effect of loneliness at T1 on depressive symptoms at T3 was β = 0.20 (95% CI, 0.11-0.28) and was reduced to β = 0.08 (95% CI, -0.04 to 0.20) after the inclusion of the multilevel resilience factors. The total effect of depressive symptoms at T1 on loneliness at T3 was similar (β = 0.21; 95% CI, 0.13-0.28) with the direct effect of β = 0.01 (95% CI, -0.08 to 0.11) after the inclusion of the multilevel resilience factors. Regarding specific indirect effects, individual-level global resilience (depression symptoms at T3 only) as well as the interpersonal-level relationship reliability and confidence (loneliness at T3 model only) factors were statistically significant. Multilevel resilience factors mediated the bidirectional relationship between loneliness and depression symptoms. Mental health interventions should consider implementing resilience-informed strategies that mitigate depression symptoms and loneliness among older SMM.