Over the past decade, a range of efforts have been made to incorporate practices drawn from industrial and participatory design into elements of the public policymaking process. Our interest lies in the field of co-design in policymaking. This emerging field has seen considerable emphasis placed on informing policy development with knowledge and insights from those living with specific problems and existing policy settings. Following the extant literature, we define co-design in policymaking as a participatory and design-oriented process which creatively and actively engages a diverse pool of participants to define and address a public problem. Evidence to date suggests co-design in policymaking can be especially useful in broadening participation in policy development, encouraging creative speculation about how policy choices might shape future outcomes, and prototyping policy approaches to assess their feasibility and desirability. But evidence continues to emerge regarding the barriers in many public sector settings that preclude co-design practice from greater engagement with – and influence upon – long-established, tightly-held processes of policy development. Through critical assessment of existing literature, we summarise the current state of co-design in policymaking. We then suggest promising ways policy practitioners and researchers could contribute to making co-design an embedded practice in policymaking, well-used and well-recognised for the unique contributions it can make to policy development.