The Charity Commission is writing to the British number one to resolve confusion over Kids at Heart, which has raised hundreds of thousands of pounds for children's causes.
Henman uses the name for fundraising purposes, but his organisation is registered with the commission as the Tim Henman Charitable Foundation.
The only charity registered as Kids at Heart is a tiny organisation in Princes Risborough, Buckinghamshire, devoted to the advancement of the Christian faith.
Stephen Burnhope, who chose the name Kids at Heart in 1997, three years before Henman established his charity, only became aware of his association with Britain's most famous tennis player when journalists began calling him. "It's the responsibility of the commission to avoid this sort of confusion," he said.
Caroline Lacy, a spokeswoman for IMG, Henman's management company, was unaware of another Kids at Heart until contacted by Third Sector.
Sparks, Sargent Cancer Care for Children, Honeypot and Tommy's are among the charities to have benefited from Henman's funds.