Ethical theorists often assume that the verb 'ought' means roughly 'has an obligation'; however, this assumption is belied by the diversity of 'flavours' of oughtsentences in English. A natural response is that 'ought' is ambiguous. However, this response is incompatible with the standard treatment of 'ought' by theoretical semanticists, who classify 'ought' as a member of the family of modal verbs, which are treated uniformly as operators. To many ethical theorists, however, this popular treatment in linguistics seems to elide an important distinction between agential and non-agential ought-statements. The thought is that 'ought' must have at least has two senses, one implicating agency and connected to obligations, and another covering other uses. In this paper, I pursue some resolution of this tension between semantic theory and ethical theory with respect to the meaning of 'ought'. To this end, I consider what I believe to be the most linguistically sophisticated argument for the view that the word 'ought' is ambiguous between agential and non-agential senses. This argument, due to Mark Schroeder, is instructive but based on a false claim about the syntax of agential ought-sentences-or so I attempt to show by first situating Schroder's argument in its proper linguistic background and then discussing some syntactic evidence that he fails to appreciate. Then, I use the failure of this argument to motivate some more general reflections on how the standard treatment of 'ought' by theoretical semanticists might be refined in light of the distinction important to ethical theory between agential and non-agential ought-statements, but also on how ethical theory might benefit from more careful study of the dominant treatment of modals as operators in theoretical semantics. * I appreciate support for research on this article provided by the Arts and Humanities Research Council. I would also like to thank John Broome, Davide Fassio, Stephen Finlay, Mark Schroeder, Alex Silk and a referee for this journal for helpful feedback. 1 This is Ellington's translation. In the original German, Kant uses 'sollen', which is etymologically related to the English word 'should'. For my purposes here, I will be ignoring any distinction between 'should' and 'ought'.