7 May 2016 Last updated at 20:03 BST
Their leader, Arlene Foster, will continue as first minister. The final count in Upper Bann ended on Saturday afternoon.
The DUP has 38 seats, while Sinn FÃ©in has 28, the Ulster Unionists 16, SDLP 12 and the Alliance Party eight.
Our political correspondent Gareth Gordon reports.
The Democratic Unionist Party (DUP) remains the largest in Northern Ireland after all 108 seats in the assembly were filled.