Terry wants Gallas to commit himself to the Chelsea cause by signing a new contract.
"William has been unbelievable," Terry enhused.
"We all want him to stay, and I've told him just that."
Gallas, 28, is wanted by AC MIlan who see him as the natural replacement for legend Paulo Maldini.
Barcelona could also come knocking if Gallas, as expected, announces he is not going to sign a new deal beyond the year left on his current one.
Rangers have signed South African youngster Dean Furman.
The 18-year-old is new Rangers boss Paul Le Guen's first signing.
The midfielder goes with Chelsea blessing with assistant manager Steve Clarke saying: "Obviously it's a big step up from the youth teams at Chelsea to the first team, but the lad has a lot of ability.
"I actually watched him play in a couple of games with our reserves last season and was impressed with him."