This work analyses the most important sources for manumission in Ancient Greece from a legal perspective, with the aim of unearthing the legal concepts and definitions that informed the liberation of slaves in the ancient documents. More specifically, this study will examine the legal nature of manumission in exchange for money while also analysing the legal condition of those ἀπελεύθεροι who, after their liberation, were required to perform παραμονή-services towards their former masters. This analysis will focus on the origins of manumission in Greece (which can be traced back to the Homeric poems), on the body of Hellenistic inscriptions from Delphi and Chaeronea, on some forensic speeches from Classical Athens and, finally, on the so-called ‘public manumissions’. All these sources are unequivocal in showing that, on the one hand, manumission in exchange for money had the nature of a bilateral legal transaction between the slaves’ masters and a third party, other than the slaves; and on the other hand, that the legal condition of manumitted slaves is always understood as one of freedom, independently of the possible imposition of post-manumission obligations upon them. This work ultimately shows not only that the Greeks’ conceptualisation of manumission relied on a solid understanding of key legal concepts such as slavery, freedom and ownership, but also that this institution was informed by common legal principles shared by different geographical and chronological contexts of the Greek world.