The stand-up, who portrayed headmaster Mr Gilbert in The Inbetweeners, will play a teacher who hates his job in Man Down, reports The Sun.
Channel 4's comedy commissioning editor Nerys Evans said: "Greg is in more ways than one a giant of British comedy.
"He has managed to write a joyfully funny, laugh-out-loud script. We're thrilled to be working with him on his first solo piece."
Jon Thoday of Avalon, which will produce the show, added: "We are very excited to be part of bringing Greg's brilliant comic creation to Channel 4."
Davies will soon embark on a nationwide stand-up tour entitled 'The Back of My Mum's Head'. The comic's previous tour 'Firing Cheeseballs at a Dog' was extended three times and released on DVD last year.
He is also due to star opposite former Saturday Night Live performer Andy Samberg in BBC Three sitcom Cuckoo.
