The goal of the thesis is to articulate and defend a political liberal conception of justice that provides plausible and determinate principles for the formulation and regulation of the institutions associated with children and their upbringing. It thereby offers a reply to those that are sceptical of the prospects for a compelling political liberal conception of justice that can be applied to children's upbringings. I begin by expounding an understanding of the political liberal approach that offers an immediate reply to a set of those objections that rest on mistaken understandings of the constraints political liberal approaches put on the derivation of principles of justice for children. The mistake is the failure to recognise that political liberalism is based on a substantive ideal of the citizen and of society, an ideal that is the basis for demanding certain outcomes and procedures of children's upbringings, regardless of what parents or certain cultural or religious groups think about those demands. I then detail a political liberal conception of justice based on this substantive ideal: Rawls's Justice as Fairness. I articulate and defend some interpretative and substantive differences from standard understandings of the general conception. I defend a political conception of autonomy as self-authorization utilizing recent work on conceptions of relational autonomy. I also argue that the principle of fair equality of opportunity ought to be jettisoned from the two principles of Justice as Fairness and replaced with a principle that secures certain relational conditions supportive of political autonomy as I expound it. I then turn to applying that conception to the specific issues raised by children's upbringings. I show that the conception's application to children's upbringings elicits plausible, coherent, and determinate conclusions with respect to the key issues raised by the upbringing of children. I show that the conception elicits plausible and coherent understandings of the interests that ought to be furthered on children's behalf, of how children's development over time alters how they ought to be treated, and what makes a child a child and then an adult. I address three key issues to elucidate the conception: the need for children to be brought up to be autonomous, the need for children to have the opportunity to experience the intrinsic goods of childhood, and the need for children to have an equal and socially inclusive education. I show that my conception elicits plausible and coherent outcomes with respect to all three issues, and demonstrate this through comparisons to other liberal conceptions of upbringing. I then offer an account of the distribution of child-rearing rights and obligations. I reject the popular set of conceptions of child-rearing obligations that connect responsibility for the child's existence with responsibility for the costs of upbringings. I deny these conceptions offer a plausible account of responsibility and its relationship to the distribution of child-rearing obligations. I offer an alternative account based on the notion that the distribution of child-rearing rights and obligations ought to be arranged to the greatest benefit of the least-advantaged, where this is consistent with the prior principles of Justice as Fairness. This elicits institutional schemes that plausibly and coherently fulfil the demands of children's upbringings and satisfies the reasonable claims of adults that have interests in acquiring (and not acquiring) child-rearing rights and obligations.