This self-development argument will be examined in fi ve sections. In the fi rst, what is meant by self-development will be explained more fully. Next, why it might be thought valuable-something that defenders of the argument have seldom expanded upon-will be examined. It will be argued that self-development is a plausible view of personal well-being. Third, there is the matter of whether it always contributes to well-being or only sometimes, and whether it is the only or the highest component of wellbeing. The fourth and most important step of the argument is to show that self-development requires liberty. Do restrictions of freedom undermine self-development, or can such restrictions further people’s development? Several arguments for the former will be examined, and the conclusion reached is that self-development provides some, but only qualifi ed, support for individual liberty. Finally, in the fi fth section an ambiguity with the idea of self-development will be pointed out. This ambiguity aff ects the argument at the most fundamental level, for one way of resolving the ambiguity means that self-development supports freedom only in the qualifi ed sense, while the other way of resolving it supports freedom in a less qualifi ed way, but at the cost of making the argument question-begging.