This paper focuses girls and young women in development policy using a ‘Smart Economics’ rationale. Using the example of Nike Foundation’s ‘Girl Effect’, the paper analyses the role ‘Smart Economics’ plays in investing in women and younger generations for developmental efficiency. Investing in girls appears to be driven not only by imperatives of ‘female empowerment’, but also to realise more general dividends for future economic growth and poverty alleviation. While 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 prioritised and whose agendas are primarily served by the shift from ‘Smart’ to ‘Smarter Economics’.