Staff at the legendary venue, which has operated for more than 40 years, have received support from around the globe after reporting they had been threatened with eviction.
A host of music stars and members of the public have thrown their support behind the campaign, although the club’s owners have pledged to keep the site as a music venue.
Four separate petitions have been set up, with more than 13,500 people pledging their support to save the Leadmill.
One organiser said: “If the Leadmill were to be forced to close it would mean Sheffield would lose one of its greatest cultural spaces.
“Our goal is to see Leadmill continue as a venue of culture and music within Sheffield.”
Last week, chief executive and founder of Electric Group, Dominic Madden, which owns the venue, pledged to keep the building as a music venue although its management may change.