This paper re-contextualises Popper within a Kantian tradition by examining his interaction with the Vienna Circle. The complexity of Popper's relationship to the Vienna Circle is often a point of confusion as some view him as a member of the Vienna Circle while others minimise his association with this group. This paper argues that Popper was not a member of the Vienna Circle or a positivist but shared many neo-Kantian philosophical tendencies with the members of the Circle as well as many of their philosophical problems and interests. By better understanding the influence of the Circle's members upon Popper, we not only remove the myths surrounding Popper's positivism, but also place the logical positivism of the Vienna Circle within its proper philosophical context. This paper further argues that it was Popper's friend during his formative philosophical years in Vienna, Julius Kraft (1921-1960) who was responsible for the way in which Popper approached Kant. Through Kraft, Popper was introduced to the thought of Leonard Nelson (1882-1927) and Jakob Fries (1773-1843) as well as a tradition of critical rationalism which Popper would continue both in his methodological orientation as well as through his late German Enlightenment intellectual values.