ABSTRACT This paper examines whether grounding can be naturalized. We adopt a tripartite framework—O cat (scientific catalogue of existents), O typ (ontological types), and metaphysics (natures/modal profiles)—and show that classifying as such the relata of putative grounding claims forces a dilemma. When the relata belong to O cat , ‘ground’ merely paraphrases logical or scientific explanatory relations already available and adds no explanatory value. When they belong to O typ or to metaphysics, the relation floats free of scientific warrant and cannot be naturalized. Surveying canonical cases (Fine; Schaffer) and general programs (monism; ontic structural realism), we conclude that naturalistic grounds of grounding are unavailable: the notion is either otiose to the scientific discourse, adding nothing to it, or detrimental if competing with it.