Trustees of the museum, in Stockwell, said lack of funding had forced the closure of the museum, which was established in 1992 and has records of every font sold to printers across the world.
Director Howard Bratter admitted the museum faced a funding crunch, but refused to elaborate.
"The trustees have not issued a statement about the affairs or state of the museum at the moment. We are in financial hardship," he said.
Writer and print historian Caroline Archer said: "It is a unique record of the typographic history of the British printing industry and is a tragic loss. Every single font sold to every printer in the UK and the rest of the world is recorded in this treasure trove of information, alongside fascinating hardware."
The museum has used grant aid in the past to buy equipment including traditional typefounding from Stephenson Blake & Co in Sheffield. The collection includes woodletter type from Robert DeLittle, York, and hot metal materials from the Monotype Corporation.
"This is a unique collection that you wont find anywhere else. It would be a great tragedy if the archive became unavailable for research," said Archer.
Type Museum to close due to funding crisis
A trove of print kit, fonts and memorabilia, billed as a "world showcase", is under threat after the closure of Londons Type Museum was announced last week.
