Background: There is limited population-based research examining mental health (MH) service use across distinct patterns of intergenerational child maltreatment, which is crucial to understand links and appropriate responses. Objectives: To examine the prevalence, frequency, timing, and types of MH service use across the intergenerational maltreatment groups: maltreated parents with maltreated children (cycle maintainers), maltreated parents with non-maltreated children (cycle breakers), non-maltreated parents with maltreated children (cycle initiators), and no maltreatment in either generation (comparison group). Participants and settings: Data were drawn from a longitudinal administrative data repository from Queensland, Australia (n = 32,494). Intergenerational maltreatment was measured using child protection system (CPS) contacts. MH contacts were measured using community MH service usage and mental illness diagnoses upon hospital admissions. Methods: Multinomial logistic regressions were conducted with the full sample to assess differences in MH contacts. Binary logistic regressions were conducted limited to the maltreatment groups (i.e., excluding the no maltreatment comparison group). The mean counts of community MH contacts and MH hospital admissions by age were plotted. Results: Compared with breakers, maintainers were more likely to have community MH contact (OR = 4.18), 3+ MH hospital admissions (OR = 5.85), and a psychiatric ward admission (OR = 3.39). Compared with breakers, initiators were also more likely to have community MH contact (OR = 2.35), 3+ MH hospital admissions (OR = 3.17), and a psychiatric ward admission (OR = 2.28). Conclusions: The significant overlaps between MH and CPS contact suggest a need for ongoing research, and integrated consideration of MH and family risks and needs in both systems, to support positive intergenerational outcomes.