Biobased,　biocompatible,　and　biodegradable　poly(lactic　acid),　PLA,　possesses　unique　properties　that　give　it　high　potential　for　a　wide　range　of　applications.　However,　its　low　thermal　stability　and　brittleness　are　major　obstacles　for　its　use.　In　this　study,　both　the　thermal　stability　and　toughness　of　PLA　were　simultaneously　improved　via　stereocomplexation　and　reactive　blending,　by　generating　alloys　composed　of　two　PLA　enantiomers,　PLLA　and　PDLA,　together　with　poly(ethylene-ran-methylacrylate-ran-glycidyl　methacrylate),　EMA-GMA.　It　was　found　that　reactive　blending　at　200　°C　was　very　effective　in　generating　alloys　with　high　degrees　of　stereocomplex　(sc)　crystallinity　and　that　the　interfacial　reaction　between　PLA　and　EMA-GMA　contributed　to　a　significant　improvement　in　toughness.　Most　importantly,　a　(40/40/20)PLLA/PDLA/EMA-GMA　film　with　high　sc　crystallinity　exhibited　both　much　higher　tensile　impact　strength　and　thermal　stability　than　neat　PLLA,　retaining　high　storage　modulus　up　to　210　°C.　The　scPLA　alloys　also　exhibited　superior　chemical　resistance　to　neat　PLA.　Thus,　it　was　demonstrated　that　simultaneous　complexation　and　the　interfacial　reaction　transform　PLA　to　the　level　of　high　performance　materials.　©　2015　American　Chemical　Society.