Zapovednik (Russian: заповедник, plural заповедники, from the Russian заповедный, "sacred, prohibited from disturbance, committed [to protect], committed [to heritage]") is an established term on the territory of the former Soviet Union for a protected area which is kept "forever wild". It is the highest degree of environmental protection for the assigned areas that are strictly protected, and maybe restricted to the public.

The closest English term is "scientific nature reserve" or literally nature sanctuary (compare to animal sanctuary), however zapovediks are not necessarily connected with nature only as there could be historical-cultural, historical-archeological, and other types of zapovedniks of cultural or natural heritage.

The term was used in the former Soviet Union and still is in the Russian Federation as well as in some of the other 14 former Soviet republics. Human use is generally limited to scientific research or educational purposes. However, many reserves have areas with different degrees of protection, and sometimes other activities (such as grazing) are permitted to a certain extent. Zapovednik refers to the reserve, staff and infrastructure.