The results of the June 7 vote mean that Turkey is bracing for a coalition for the first time.
The opening of the single-chamber parliament, the Grand National Assembly of Turkey, is a largely ceremonial affair, with each of the 550 deputies individually swearing oath in a marathon event starting at midday GMT that risks dragging on into the early hours of the morning.
But the meeting also fires a starting shot for the parties' formal efforts to agree a coalition after an election seen as one of the seismic events in Turkish politics in recent decades.
It also starts the process to elect the new parliament speaker, with parties set to propose their candidates in the next five days.
While the AKP emerged as the largest party, the results were a blow not only to its authority but also President Recep Tayyip Erdogan, who had been hoping the new parliament would agree on a new constitution to cement his powers.
The elections were seen as clipping the wings of Erdogan, who served as premier from 2003-2014 before becoming president last year and is now based in a vast and controversial new presidential palace on the outskirts of Ankara.
The AKP have 258 seats in the 550-seat parliament, the Republican People's Party (CHP) 132, and the Nationalist Movement Party (MHP) and pro-Kurdish People's Democratic Party (HDP) 80 apiece.