Sergei Kovalev (1930–2021) was a Russian human rights activist.
Sergei Kovalev, Sergei Kovalyov or variations may also refer to:
Sergey Kovalev (born 1983), Russian boxer Sergey Kovalev (historian) (1886–1960), Soviet historian Sergei Kovalyov (footballer, born 1965), Russian footballer Sergei Kovalyov (footballer, born 1972), Russian footballer Sergei Nikitich Kovalev (1919–2011), Russian submarine designer