The drive to turn vast amounts of activity and human behaviour into data points that can be tracked, collected and analysed has become a significant feature of contemporary social life; what has been described as the ‘datafication’of society. With these developments we are confronted with a significant shift in governance and a fundamental transformation of statecorporate-citizen relations. Whilst this is often hailed as ‘revolutionary’in its potential for enhanced efficiency, security and innovation, we have also seen an increasing concern with the societal implications of these developments. In particular, a growing body of research has pointed to the multiple ways in which datafication both introduces and entrenches key questions pertaining to a broader concern with social justice, such as issues of inequality, discrimination, and exclusion. In this blog post, we want to contribute to the discussion on how to approach the relationship between data and social justice and apply it to what we understand by data justice, as part of our DATAJUSTICE project. Drawing on key literature we have discussed in our on-going project-based reading group that started in February 2018, we begin by outlining some of the rationale for privileging social justice in our discussion of datafication. We then go on to outline some central ideas about justice and what this might mean for studying and advancing data justice as a research and practice agenda. Our central understanding of data justice is to take impacted communities and social groups as our starting point for exploring existing and potential injustices, including in the form of oppression and domination, and to situate data processes within historical and on-going struggles for justice claims. We intend for this to serve as the beginning of our discussion, rather than as a definitive interpretation, and welcome comments and suggestions as we develop our ideas further over the next few years.