Care ethics is primarily about responding to needs. Yet, surprisingly, attempts to apply the ethics of care in the domain of law have paid almost no attention to the concept of legal needs. This study fills that gap by systematically defining legal needs. It does this by revising current understandings of legal need through a unified conceptual framework for the philosophy of needs and a comparative analysis of legal action, and its major alternatives in dispute resolution and prevention. The conception of legal need that results is both more sensitive to preventative functions of the law and opens the door to a much wider range of policy options beyond legal aid. Legal needs are found to be a special case of institutional needs, i.e. needs that cannot be satisfied without an institution. I argue that the existence of institutional needs means institutions, rather than any particular actor within them, can be caregivers, but not all conceptions of the ethics of care are compatible with this kind of need. Joan Tronto’s conception of care is found to be the most accommodating and is used as a framework for a series of policy recommendations to move us towards a caring legal system.