What constitutes a good Stevie Smith poem? The question bothered the author herself and it can bedevil the reader too, with evaluative quandaries often compounding interpretive ones. Smith’s uncertainty about the relative merits of her poems informed publication decisions, and this in turn has resulted in certain compositions being overlooked in critical assessments of her achievement. This article takes as a test-case example a hitherto largely neglected poem, ‘The Ballet of the Twelve Dancing Princesses’, and through sustained close reading makes the case that the poem, unpublished in Smith’s lifetime, may be one of her finest pieces. Through an analysis of the poem’s cultural and historical context, its manifold ambiguities, its imagery and atmosphere, its coded engagement with the fabular and the strange effects achieved through rhythm and rhyme, the poem is shown to offer a complex, psychologically suggestive response to issues which exercise Smith in many of her poems, including the tension between innocence and knowledge, between the child and the adult, between the capricious and the calculated, and between the ‘frivolous’ and the ‘ominous’. The difficulty of determining how ironically and how seriously Smith engages with some of the latent preoccupations of her poem, such as the power of sorcery and the supernatural, the growth of sexual awareness in young girls and (possibly) the approach of the Second World War, is taken as symptomatic of the tendency of Smith’s poems to at once invite and defy exegesis. Taken together, these various concerns and characteristics provide the grounds for considering one of Smith’s overlooked poems as one of her most effective. Yet the conclusion seeks to complicate this assessment by cross-questioning the criteria by which Smith’s ‘success’ as a poet may be determined.