In the context of the increased interest in social justice within education policy debates, this article addresses the new justice-oriented school admission system implemented in Chile. Considering the critical role of parents in education policy, we explore families' negotiations about the new school admission system, focusing on the moral dilemmas they experience when confronted with changes in the rules that organize the distribution of school seats and the notions of educational justice they adhere to. We draw on interviews with 80 families from different social classes and belonging to five regions of Chile who were choosing a school under the new school admission system. Our findings underline that--while families tend to agree with the principle of equal formal opportunities in the school admission field--the reform brings in a set of moral dilemmas and competing notions of justice that encompass its different components. Based on these findings, we shed light on the distance between policy intention and interpretation, and between abstract conceptualizations of justice in educational policies and what counts as just policies in families' views. In addition, we outline a set of implications for justice-oriented reforms worldwide.