Law is both shaped by and a vehicle for hierarchically structured dichotomies that fragment life, thought and action – most enduringly the split between scholarship and activism. This article revisits investigación militante, a Latin American and Caribbean tradition that rejects the separation between theory and practice, and between academic inquiry and political struggle. Through the work of Orlando Fals Borda, Lélia Gonzalez and Silvia Rivera Cusicanqui, we explore how investigación militante offers a distinctive onto-epistemological and ethical orientation for law and society research. Concepts such as senti-pensar, amefricanidade and ch’ixi open up approaches to law as a terrain for co-producing alternative normativities. We identify three core commitments – methodological, political and ethical – that distinguish investigación militante from adjacent approaches such as movement lawyering, offering critical resources for re-imagining law and society praxis amid intersecting planetary crises.