Sir Alan, whose first three-year term comes to an end in September 2017, will now serve until the end of 2019.
He has served as chairman of IPSO since the body’s foundation.
Sir Hayden Phillips, chairman of the independent IPSO Appoints Panel, said: “Sir Alan became the founding Chairman of IPSO at a febrile time for press regulation. Since then IPSO has become fully established as the respected, independent regulator of UK newspapers and magazines.
“The success of the organisation owes much to Sir Alan’s leadership and integrity. The panel was unanimous and enthusiastic in offering him a new contract.”
Sir Alan added: “IPSO has achieved much in the first three years, but there is more to do. I have been well supported by the Board and Complaints Committee and above all by IPSO’s staff.
“I am looking forward to reinforcing IPSO’s independence and effectiveness in my second term.”