Sterile neutrinos in the eV-mass range has been proposed as a possible solution to several anomalies observed in neutrino laboratory experiments. However, the best fit mass is in strong tension with cosmological bounds on the sum of neutrino masses. One way to relieve this tension is by invoking non-standard production scenarios.

In this talk I will give an overview of the different proposed production scenarios and review the cosmological bounds on sterile neutrinos.