The broadcaster is currently airing season two of the hit US drama, which stars Claire Danes and Damian Lewis, attracting up to three million viewers.
Bosses were said to be concerned another channel could pick up the show, as has happened in the past with shows such as Lost, which Sky outbid Channel 4 for in 2006.
A third season of Homeland is yet to be officially confirmed, but Lewis was recently rumoured to have signed a new five-year deal to continue playing Nicholas Brody.
Channel 4 boss Jay Hunt told The Sun: "Homeland has become unmissable TV. I'm delighted we have the third season for Channel 4 viewers to enjoy."
A source added: "Following the 'shout at the TV' end to last night's show, the Homeland team continue to set pulses racing.
"It's been a thrilling journey so far and with series three secure on Channel 4, we, like everyone else, are on the edge of our seats waiting to see where they take us next."
Filming of season two is still under way. The third season is expected to premiere next year.
Watch Damian Lewis told to Digital Spy about Homeland below: