A range of amphiphilic diblock and triblock copolymers based on poly (2-methyl-2-oxazoline) (PMeOx) and poly (D, L-lactide) (PLA) with various compositions and molecular masses were prepared combining cationic ringopening polymerization and click chemistry. Their hydrophilic weight ratios (f) covered a wide range of composition (21-77%). In water, these amphiphilic copolymers self-assembled to form, in the case of diblock copolymers, core-shell micellar structures with a dense PLA core and a hydrated PMeOx shell in the whole range of f values. The triblock copolymers formed micellar aggregates of finite sizes made of bridged micelles, the micelles being connected by some of the PLA end-blocks. Moreover, the micelles displayed original core-multishell nanostructures in a specific range of f values (48%), never reported for this kind of triblock copolymers. The amphiphilic copolymers of this study displayed a rich variety of controlled self-assembled morphologies which could be promising candidates for drug delivery applications.