Truthmaking is the metaphysical exploration of the idea that what is true depends upon what exists. Truthmaker theorists argue about what the truthmaking relation involves, which truths require truthmakers, and what those truthmakers are. This Element covers the dominant views on these core issues in truthmaking. It also explores some key metaphysical topics and debates that are usefully approached by employing the tools of truthmaker theory: the debate between presentists and eternalists over the existence of entities from the past, and the debate between actualists and possibilists over merely possible states of affairs. In the final section, the Element explores how to think about truthmakers for truths involving social constructions.