The BBC show, which features characters such as teenager Vicky Pollard and Dafydd 'the only gay in the village', triumphed over The Office Christmas Special in the best TV comedy category and the people's choice category at the British Comedy Awards last night.
Walliams and Lucas also jointly won the best TV comedy actor award.
Little Britain first appeared as a Radio 4 series and was then commissioned by BBC3, where it captured the channel's highest ever audience. The second series recently made its terrestrial debut on BBC1.
The talent behind The Office , Gervais and creative partner Stephen Merchant, however, were recognised with a special writing award.
Meanwhile, Caroline Quentin picked up the best TV comedy actress award for her appearance in ITV shows Life Begins and Von Trapped and Catherine Tate ( The Catherine Tate Show ) went home with best comedy newcomer award.
ITV1 show Doc Martin was awarded best TV comedy drama over Channel 4's Shameless.
Presenting duo Ant and Dec also had a good night, picking up best comedy entertainment personality and best comedy entertainment programme for Saturday Night Takeaway.
The best international comedy award went to long-running US series The Simpsons and creator Matt Groening also received an outstanding contribution award from scientist Stephen Hawking.
Winners in full:
Best TV comedy actor
Matt Lucas & David Walliams ( Little Britain , BBC Three)
Best TV comedy actress
Caroline Quentin ( Life Begins/ Von Trapped , ITV1)
Best comedy entertainment personality
Ant & Dec ( Ant & Dec's Saturday Night Takeaway/ I'm A Celebrity, Get Me Out Of Here! , ITV1)
Best comedy newcomer
Catherine Tate ( The Catherine Tate Show , BBC Two)
Britain's best new TV comedy of 2004
Nighty Night (Baby Cow Productions, BBC Three)
Best TV comedy
Little Britain (BBC Three)
Best TV comedy drama
Doc Martin (Buffalo Productions, ITV1)
Best comedy entertainment programme
Ant & Dec's Saturday Night Takeaway (Granada, ITV1)
Best international comedy show
The Simpsons (Twentieth Century Fox, BBC Two/Sky One/Channel 4)
Best comedy film
School Of Rock