It will run until 15 January, when goods will be collected and donated to a range of charities, including the British Heart Foundation, the Julian Trust Night Shelter and FareShare.
It follows on from the hugely successful city-wide Bristol Big Give, which was a joint initiative with Bristol City Council, the University of Bristol, the University of Bristol Students' Union (Bristol SU), the University of the West of England, UWE Students' Union (UWESU) and their charity partners.
Donations amounted to 73 tonnes collected throughout May and June – the equivalent to £125,660 when sold.
Sarah Redrup, Student Living Officer at Bristol SU, said: "We all have stuff in the back of our cupboards that we don’t want, whether it's a jumper you haven't worn for ages or a tin of vegetables you know you'll never eat. The Christmas Big Give is an opportunity for students to have a clear out, either before or after Christmas, and do a good deed at the same time."
Updates are available on the Bristol Big Give Facebook page.