Introduction: Research has found low levels of help seeking for alcohol problems among serving and ex-serving military populations. This study aimed to understand the prevalence of, and factors associated with, help seeking for self-reported alcohol problems among serving and ex-serving UK military personnel. Methods: Regular and full-time reserve serving and ex-serving personnel in a large UK military cohort (N = 6,199) were asked whether they had an alcohol problem in the past three years and whether and where they sought help. Associations between help seeking from formal medical services (general practitioner/medical officer, hospital doctor) and socio-demographic, military, life, and health factors were examined using weighted survey methods. Results: A total of 8.5% (n = 461) self-reported an alcohol problem, 71.1% of whom had not sought help. Formal medical services were the most accessed support overall but were significantly less likely to be used by older personnel. Those meeting current caseness for probable alcohol misuse (Alcohol Use Disorders Identification Test score ≥ 16; adjusted odds ratio = 0.54, 95% confidence interval, 0.31-0.95, p = 0.032) were less likely to have previously accessed formal support. Discussion: Help seeking for self-reported alcohol problems among UK serving and ex-serving personnel remains low. Future research should prioritize understanding pathways into help seeking and target stigma regarding accessing clinical support among both serving and ex-serving personnel.