The species occurs in primary and secondary deciduous, coniferous and mixed forests, as well as open areas with small patches of forest enclaves and forest steppe. It is also found along river valleys. It feeds on small mammals, such as voles, squirrels, mice and pikas, amphibians, fishes, and carrion, and occasionally on vegetative matter (e.g. pine nuts) (Heptner et al. 1967).

This species is of marginal occurrence in Europe, where it is found only in eastern regions of European Russia up to the Ural Mountains.

The Siberian Weasel (Mustela sibirica) species has one of the largest distribution ranges in the Palaearctic among small mustelid species, with the exception of the stoat Mustela erminea and least weasel M. nivalis. 

The Siberian Weasel is widely distributed across the East Palaearctic, from Eastern Europe (Kirov Oblast and Tatarstan in Russia) eastward to the Pacific coast and southward to the Himalayas; however, the Siberian weasel does not occupy a large part of arid Central Asia (southern Mongolia and northwest China) (Heptner et al. 1967, Abramov et al. 2018). It occurs on a few Pacific islands (Jeju, Tsushima and Taiwan) and it has been introduced to Honshu, Shikoku and Kyushu in the Japanese islands (Sasaki 2008). The southern and southwestern limits of its distribution range are poorly known; the records from Laos, Vietnam and Thailand are incomplete and unconvincing.

No conservation action is recorded in Europe for this marginally occurring species.