Purpose: This study aims to set out to develop and validate a new instrument to measure the multi-dimensional nature of co-opetition in corporate responsibility and sustainability (CRS). It is anticipated that this instrument will prove useful to firms wanting to adopt measures that support relevant sustainability strategies. Design/methodology/approach: The scale development concerns three separate components, namely, item generation through expert interviews; a pilot study conducted for scale purification; and a final study for scale confirmation and validation, respectively. The final study comprises 215 firms across 11 sectors in Australia that engage in co-opetitive alliances for CRS activities. Findings: This study empirically validates the distinctiveness of three dimensions (commonality-driven, competition-driven and collaboration-driven) of co-opetition in relation to CRS resulting in a 15-item multi-dimensional scale. The three dimensions were found to be important aspects both in terms of scale validity and organisational consideration. Research limitations/implications: This study proposes a new research area regarding the proposed framework, as well as practical strategies for practitioners when considering co-opetition and their firm’s engagement in CRS activities. Originality/value: Prior studies in similar areas have mainly comprised conceptual or qualitative approaches and do not tend to focus on all three aspects of co-opetition, corporate social responsibility and sustainability.