Addressing the news conference called at short notice on Wednesday, Sommaruga said family reasons made her take the decision after her husband suffered a stroke.
Sommaruga has been a member of the government since 2010 as justice minister and then as transport, energy, environment and communications minister from 2018.
She also served as Swiss president in 2015 and 2020.
Sommaruga, who’s 62, is the second cabinet minister to announce her resignation for the end of the year, following the finance minister, Ueli Maurer.
Parliament is due to elect successors for Sommaruga and Maurer on December 7.
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