The formation of dispersions of amphiphilic block copolymer particles with the controlled morphology via heterophase polymerization mediated by reversible addition-fragmentation agents is considered. Variants of dispersion, emulsion, and seeded polymerizations are analyzed, and the mechanism of this process is discussed. Special attention is focused on issues related to control over the morphology of the formed particles immediately during synthesis and methods of its transformation in the resulting dispersions.