We explain libertarian thought about family and children, including controversial issues in need of serious attention. To begin our discussion of marriage, we distinguish between procedural and substantive contractarian approaches to marriage, each endorsed by various libertarians. Advocates of both approaches agree that it is a contract that makes a marriage, not a license, but disagree about whether there are moral limits to the substance of the contract with only advocates of the substantive approach accepting such. Either approach, though, offers advantages over the current licensing system, so we discuss paths from that to a contractarian system. We also discuss the concept of marriage itself, the ages of consent for marriage, sexual activity, and reproduction, as well as how marriages can be dissolved, and coercion that sometimes occurs in marriage. We then turn to children. We first discuss reproductive freedom and then discuss the moral relationship between children and parents, especially considering stewardship, propertarian, and best interests approaches (we also touch on anti-natalism). One of the biggest issues facing parents is how to properly raise and educate children; we discuss this in depth and consider the sort of schooling that should be offered in a free society. Since children lack the requisite ability to consent, they cannot choose their education; how to respond to this is of the utmost importance for libertarians. As we note, the same issue of consent looms large for many forms medical treatment of children.