The Palestinian electoral commission announced on Sunday that it had approved all the 36 applications.
The groups had until Wednesday to submit their lists of candidates for the May 22 polls.
The vote is part of an effort by key Palestinian factions, including Fatah and Hamas, to boost support for Palestinian governance.
The Palestinian leadership has been divided between Fatah and Hamas since 2006. Back then, Hamas scored a landslide victory in parliamentary elections in the besieged Gaza Strip.
Hamas has ever since been running the densely-populated coastal enclave, while Fatah has been based in the autonomous parts of the occupied West Bank.
In January, Palestinian President Mahmoud Abbas announced the 2021 elections would also include presidential vote on July 31 and the National Council elections slated for August 31.
Leaders of fourteen Palestinian political groups have already held a comprehensive national dialog to reach an agreement on the mechanism of holding elections in the occupied Palestinian territories.
While Fatah and Hamas have reached an agreement for the voting to take place in the West Bank and Gaza, it remains opaque whether the Palestinians in the occupied East Jerusalem al-Quds would be able to vote. Palestinian leaders want the voting to be held in the east, the area where they see as the capital of a future Palestinian state.
Abbas has said he would not agree to elections unless Palestinians in East Jerusalem al-Quds can vote. Such a guarantee is unlikely.
Palestinian factions in recent months have announced a unified stance against attempts by Israel, the United States and some Arab countries to undermine the Palestinian cause, denouncing any form of normalization with the occupying regime as “a stab in the back” of not only the Palestinians but the entire Muslim world.
Relations between the Palestinian Authority and the United States soured after the administration of former President Donald Trump recognized the whole Jerusalem al-Quds as the “capital” of Israel and moved the US embassy from Tel Aviv to the city. The former US president also cut aid to Palestinians in the West Bank and proposed a much-condemned plan – known as the Deal of the Century – that allowed Israel to seize large parts of the West Bank and the Jordan Valley.