Background Current Australian mental health policy recommends that carers should be involved in the provision of mental health services. Carers often provide intensive support to mental health consumers and gain detailed insight into their lives. As such, carers could make valuable contributions to well‐informed decisions about mental health consumers' use of antipsychotic medication. Objectives The aim of this study was to explore carers' participation in antipsychotic medication decision making. Methods Snowball sampling was used to enrol 29 carers in this study. Of these carers, 19 participated in semi‐structured interviews, and ten participated in a focus group. Data were analysed thematically. Results Four main themes emerged from the analysis. The findings highlighted that carers typically received little or no information about antipsychotic medication. Carers commonly addressed the shortfall in information by obtaining additional information through online sources or distributing among carer networks material that they had developed themselves. Almost all carers emphasized that they should be involved in decisions about antipsychotic medication, but noted that they were typically excluded. The lack of involvement in medication decisions was a source of frustration, as carers could contribute saliently through sharing detailed knowledge about mental health consumers' lives, address communication gaps that resulted from disjointed care and improve communication between health professionals and mental health consumers. Conclusion Health professionals could consider improving the extent to which they collaborate with carers in medication decisions.