This paper takes as starting point the fact that equity as an overall concern associated to social justice is currently a focus of attention and subject of discussion for police makers, researchers and practitioners in different educational contexts. Earlier research works highlights the fact that notions of equity are strongly influenced by historical, social and cultural factors; at the same time different sociological theories gives grounds to argue that is possible to identify a number of "aspects" which might help to consider particular policies and practices in education as more or less equitable. The paper makes a preliminary analysis of current approaches presented in research with focus on equity where three main trends are identified: (a) curriculum theory; where notions of equity are analyzed following a historical perspective associated to curriculum development, (b) equity indicators; where equity is argued to be associated to indicators which feasible assessing whether specific policies and practices are equitable or not, and (c) equity practices, where the focus of the enquiry is mainly on what is possible and implemented in specific settings and the tensions associated. The paper brings forward for discussion the question about the possibilities for these identified trends to converge in cross-national comparative studies and the theoretical and methodological challenges involved.