This article traces the mounting interest in, and visibility of, girls and young women in development (WID) policy, especially since the turn of the twenty-first century when a ‘Smart Economics’ rationale for promoting gender equality and female empowerment has become ever more prominent and explicit. ‘Smart Economics’, which is strongly associated with an increased influence of corporate stakeholders, frequently through public–private partnerships (PPPs), stresses a ‘business case’ for investing in women for developmental (read economic) efficiency, with investment in younger generations of women being touted as more efficient still. The latter is encapsulated in the term ‘Smarter Economics’ with the Nike Foundation’s ‘Girl Effect’ being a showcase example. In this, and similar, initiatives linked with neoliberal development, ‘investing in girls’ appears to be driven not only by imperatives of ‘female empowerment’, but also to realize more general dividends for future economic growth and poverty alleviation. Yet, while it may well be that girls and young women have benefited from their rapid relocation from the sidelines towards the centre of development discourse and planning, major questions remain as to whose voices are prioritized, and whose agendas are primarily served by the current shift from ‘Smart’ to ‘Smarter Economics’.