Well‐defined tertiary amine‐functionalized cationic polylactides (CPLAs) are synthesized by thiol‐ene click functionalization of an allyl‐functionalized polylactide, and utilized for the delivery of interleukin‐8 (IL‐8) siRNA via CPLA‐IL‐8 siRNA nanoplexes. The CPLAs possess remarkable hydrolytic…