This article argues in favour of lowering the voting age to 16. First, it outlines a respect-based account of democracy where the right to vote is grounded in a respect for citizens’ autonomous capacities. It then outlines a normative account of autonomy, modelled on Rawls’s two moral powers, saying what criteria must be met for an individual to possess a (pro tanto) moral right to vote. Second, it engages with empirical psychology to show that by the age of 16 (if not earlier) individuals have developed all of the cognitive components of autonomy. Therefore, since 16- and 17-year-olds (and quite probably those a little younger) possess the natural features required for autonomy, then, to the extent that respect for autonomy requires granting political rights including the right to vote – and barring some special circumstances that apply only to them – 16- and 17-year-olds should be granted the right to vote.