In philosophical inquiry into the mind, the metaphor of ‘transparency’ has been attractive to many who are otherwise in deep disagreement. It has thereby come to have a variety of different and mutually incompatible connotations. The mind is said to be transparent to itself, our perceptual experiences are said to be transparent to the world, and our beliefs are said to be transparent to – a great many different things. The first goal of this essay is to sort out the different uses of the notion of transparency in the context of the philosophy of mind. The remainder of the essay will then be devoted to examining so-called Transparency theories of self-knowledge, or how we know our own minds. This type of theory has attracted a great deal of interest in recent years, but its prospects hinge on answers to unresolved questions concerning the epistemological details of the account and the scope of its ambitions.