The growth Of Cu2O crystals that are electrochemically deposited as micrometer-size crystals with systematically varying fractions of {100} and {111} faces is reported (the Figure depicts cubic crystals). The methodical and homogeneous shape evolution is achieved by tuning the degree of preferential adsorption of sodium dodecyl sulfate on the {111} faces of growing Cu2O crystals through pH variation. Scale bar: I mum.