The stand-up referred to "The Spastics Society" when talking about an upcoming benefit show on Sunday, May 20 at the Hammersmith Apollo.
However, the body changed its name in 1994 as "spastic" frequently became used as an insult.
Following the incident, Scope wrote on Twitter: "We can confirm that we've not changed our name again!
"See Ben Elton and others at *Scope's* Big Comedy Night. Thanks Ben for the plug, see you next week!"
Of the error, the charity posted a picture of Elton at the charity's '90s relaunch and continued: "We'll put that down to jet lag! He was there when we changed!
"Ben's been a huge supporter of ours for years - so we're thrilled he's involved with the comedy night! Definitely a slip!"
It added: "We're really pleased to have him headlining, even if he slipped on TV talking about it!"