The 2021 Super2 & Super3 Series was an Australian motor racing competition for Supercars, which is being staged as a support series to the 2021 Supercars Championship. It was the twenty-second running of the Supercars Development Series, the second tier of competition in Supercars racing. 2021 saw Super3 entries competing alongside Super2 Series cars as a class for the first time within the series which also marked at the same time as the fourteenth running of the Super3 Series itself (Formerly the Kumho Tyre V8 Touring Car Series before officially becoming a third-tier Supercars Series in 2019 as the Kumho Tyre Super3 Series).