The potential space, the space between the experiencer and the experience, is at the heart of Winnicott's theory. The concepts of agency of one's actions and ownership of one's experience have been recently applied to such a space lying in between the experiencing self and the mental (cognitive) map she creates, representing her surroundings. Agency is defined as "the sense that I am the one who is generating the experience represented on a mental map", while ownership is defined as "the sense that I am the one who is undergoing an experience, represented on a mental map". Here these concepts are introduced and applied to five main realizations of Winnicott's potential space: Playing, transitional phenomena, the therapeutic space, culture and creativity. Through theoretical constructs and clinical analyses, it is shown how agency and ownership, and their mutual interrelations, may help to better understand Winnicott's theory with implications to clinical practice.