<p>We argue for the claim that spacetime singularities in general relativity (GR) signal <i>indeterminism</i>, broadly construed. We first develop a schema for diagnosing a type of indeterminism for physical theories, which we denote by <span>Indeterminism</span>. Such indeterminism involves a broader notion of a <i>lack of a determination</i> than the usual Laplacian one. More precisely, <span>Indeterminism</span> arises in a model of a physical theory whenever future (or past) states of the model are (i) not unique, (ii) not specified, or (iii) ‘incoherent’—that is, they fail to satisfy desiderata that the theory should reasonably satisfy. We then apply our schema to salient features of spacetime singularities in GR. We establish that, indeed, singularities signal a type of indeterminism that cannot comprehensively be understood as a variety of Laplacian indeterminism: namely, spacetime singularities in GR signal <span>Indeterminism</span>.</p>