In this paper, we discuss Armstrong’s account of attachment-based claims to natural resources, the kind of rights that follow from attachment-based claims, and the limits we should impose on such claims. We hope to clarify how and why attachment matters in the discourse on resource rights by presenting three challenges to Armstrong’s theory. First, we question the normative basis for certain attachment claims, by trying to distinguish more clearly between different kinds of attachment and other kinds of claims. Second, we highlight the need to supplement Armstrong’s account with a theory of how to weigh different attachment claims so as to establish the normative standing that different kinds of attachment claims should have. Third, we propose that sustainability must be a necessary requirement for making attachment claims to natural resources legitimate. Based on these three challenges and the solutions we propose, we argue that attachment claims are on the one hand narrower than Armstrong suggests, while on the other hand they can justify more far-reaching rights to control than Armstrong initially considers, because of the particular weight that certain attachment claims have.