Armored ground attack aircraft, overshadowed by the Il-2. Su-6 was more advanced than the Stormovik, its air-cooled engine did not require armoring and provided more power. But Il-2 production was already 'in full steam', and switching to radically new aircraft could be harmful for production rate. Importantly, the Su-6 inherited chronic problem of the Su-4 - it relied on experimental engines.

Development started in 1939. Second Su-6-2 (improved) version was built in 1942, and the last one (Su-6-3), powered by liquid-cooled 2000hp AM-42 started flight testing early in 1944.