The two companies, which have worked together for the last four years, will continue the relationship into the foundation stage of the smart meter roll out in the UK.
The pair also announced that they are working on developing pre-payment capacity in smart meters.
Andy White, chief executive at Trilliant, said: “Trilliant has spent the past four years building a critical component of British Gas’ smart meter rollout.
“We are delighted that this has been such a success and that British Gas has the trust in us to deliver on a much larger scale.”