Silicone-modified polyvinyl acetal copolymers are prepared by copolymerization of at least one vinyl ester monomer and a copolymerizable silicone macromer followed by hydrolysis to a partly or fully hydrolyzed polyvinyl alcohol copolymer and subsequent acetalation with at least one aldehyde. The copolymers have numerous uses in sectors where polyvinyl acetals are useful.