We discuss the phenomenology of third generation sfermions paying particular attention to the implications of the Yukawa couplings and to the left-right mixing. Analytical formulae are given for the sfermion mixing, the production cross sections at e+e- colliders, and for all possible two body decay widths that can occur at tree level. In case of the light stop stop we give in addition the analytical formulae for the most important three body decay widths. We give detailed numerical discussion of the various production cross sections at LEP2 and a future e+e- Linear Collider. We discuss the various decay channels paying particular attention on the decays into Higgs and vector bosons, and on the three body decays of the light stop.