Abstract: This Essay explores the shadow of administrative law. A good deal of government authority that is administrative for all intents and purposes is wielded by organizations and institutions that are not legally classified as administrative agencies. Some of these entities are private firms; some are hybrid organizations within the government. Others are traditional parts of the bureaucracy that have been deemed non-agencies for purposes of the Administrative Procedure Act (“APA”), as a matter of statutory or regulatory interpretation. Across a range of heterogenous contexts, federal courts often apply administrative law principles, derived primarily although not exclusively from the APA, as legal constraints on these actors, even though the law on its terms does not apply. Although formally outside the domain of administrative law proper, they remain covered by administrative law’s shadow. The Essay assembles and analyzes some of the cases in the shadows in an attempt to clarify the judicial practice, locate it in the context of conventional debates about administrative common law, and then offer some speculation about new contexts in which judging from the shadows may emerge.