BACKGROUND: The evidence base for child-focused domestic abuse (DA) interventions is weak. Part of the challenge is that studies measure a range of different outcomes using different outcome measurement instruments (OMI). To address this, a core outcome set (COS) comprising five outcomes was developed. The current study aimed to: (1) identify relevant OMIs and assess their quality for three outcomes in the DA-COS (family relationships, feelings of safety, freedom to go about daily life); and (2) reach consensus between participants on acceptable OMIs for use in research and practice contexts. METHODS AND RESULTS: We carried out a four-stage mixed-methods process to identify, appraise, and reach consensus on relevant tools including targeted, systematic literature searches, participant workshops to define outcome concepts, OMI appraisal of psychometrics and acceptability, and a multi-participant consensus workshop to reach consensus on OMI selection. In total, 239 OMIs were initially identified and reduced to 18 through a systematic appraisal process. Following a rating process of acceptability and feasibility, eight OMIs were taken to a final consensus workshop which resulted in the identification and provisional recommendation of two subscales from a newly developed tool for family relationships and feelings of safety. No suitable OMI was recommended for freedom to go about daily life. DISCUSSION: This work is the next step toward the development of a child and family-focused DA-COS, that we hope will enable co-ordinated outcome measurement within and between practice and research. Further work is needed to adapt and evaluate the selected OMI as well as to develop a new tool to measure freedom to go about daily life. Work is needed to support the implementation of the DA-COS, ensure its applicability to families with diverse needs or from underserved communities and to track the benefits and potential harms of its use in this field.