AbstractTo examine the mental health and caregiving needs of significant others (including partners, parents, friends) to women who received acute psychiatric care either as inpatients or at home during the perinatal period. Cross-sectional survey of 98 significant others of 279 women who participated in a quasi-experimental cohort study of services for mothers with acute severe postpartum mental health diagnoses. Significant others completed an adapted General Health Questionnaire-12 (GHQ) and Involvement Evaluation Questionnaire (IEQ) to indicate their mental health needs and service use as well as caregiving activities. The mean age of significant others was 38.9 years (range 24–69). 81.6% were male and 81.6% were intimate partners to the women. High levels of unmet mental health needs were detected in significant others, with a majority (51.0%) having a score > 2 on the GHQ-12 indicating caseness for a psychiatric disorder. In those with GHQ-12 caseness indicated, few were receiving help for their difficulties: 22.5% received support from their general practitioner, and 14.3% received help from a social worker, psychologist, psychiatrist or outpatient department. 18.4% received medication for GHQ-12 symptoms. The median sumscore of IEQ surveying caregiving activities in significant others was 18/108. We did not find evidence of differences in GHQ-12 or IEQ scores for significant others to women who received inpatient care versus care at home. Significant others to women with acute severe postpartum psychiatric illness have high levels of unmet mental health needs during the weeks after women are discharged from acute care. Services need to address these needs to optimise outcomes for the whole family.