GP3 organisers will permit teams to field more than the customary three cars starting from 2016, with the number of entered teams down to seven.
The series has mandated three cars per team since its inception in 2010 but the arrival of the championship's third-generation car in 2016 will see the limit raised to four.
"I am pleased to announce that our GP3 teams will be allowed to line up a fourth car next season," said series boss Bruno Michel.
"It is something that has been discussed between us and the teams this year and I feel that it will give them an even stronger financial base for the season to come."
GP3 has simultaneously unveiled an updated list of teams entered for the 2016-18 cycle, which no longer features Virtuosi Racing.
The British team, which runs the Russian Time operation in GP2, was on the earlier team list alongside fellow newcomers DAMS, but only the French squad is now set to make its GP3 debut in 2016.
2016-18 GP3 teams' entry list
|ART Grand Prix|