Upon irradiation, the photosensitizer pheophorbide-a causes dramatic morphological transitions in giant unilamellar lipid vesicles. This endocytosis-like process occurs only when the photoactive species are encapsulated in a copolymer nanocarrier and strictly depends on the chemical nature of the copolymer. Altogether, these results open up new perspectives in the field of photo-chemical internalization mediated by nanoassemblies.