Barca did not specify the details of the agreement, nor did they reveal which issues had remained unsettled prior to Monday's agreement.
Neymar's €222 million move to PSG in 2017 had led to several court cases between the two parties, with Neymar demanding Barca pay him an unpaid renewal bonus and the club responding by suing him for breach of contract.
"Barcelona have ended out of court in amicable fashion the various labour and civil litigation cases that were open with the Brazilian player Neymar," the Blaugrana said in a statement on Monday.
"As such, a transactional agreement between the club and the player has been signed to end the legal cases that were pending between the two parties."
Neymar moved to Barcelona from Brazilian side Santos in 2013 and his time at the club -- and the years since his departure -- have been littered by off-field problems.
Former president Sandro Rosell resigned in 2014 when a Spanish judge agreed to hear a lawsuit alleging the real cost of the deal had been hidden in false contracts.
Barca initially said Neymar had cost them €57 million but it was later revealed the real price was closer to €80m. A company owned by Neymar's father had received a large percentage of the final fee.
The club were eventually charged with tax fraud and paid a voluntary €13.6m to close the case in an attempt to save the club's image.
As a result, DIS Esporte, who earned 40% of Neymar's economic rights when he was a Santos player, also filed a lawsuit as they believed they had not been paid what they were due from the deal. Criminal cases were never brought against the club.
Neymar's move to PSG in 2017 then opened several legal issues between the player and Barca.
Last July, he was ordered to pay Barcelona €6.7m following a dispute based around a €43m renewal bonus included in the last contract he signed with the club in 2016.
He received around €14m of the bonus before leaving Barca, who deposited the remaining amount with a notary once it became evident he was signing for PSG.
When he signed for PSG in a world record deal, he demanded Barca pay the rest of the bonus. Barca, represented by Costa-Torrecillas-McCragh, responded by suing him for breach of contract and requested the return of the €14m already paid to Neymar as well as €8.5m in damages plus interest.
A judge sided with Barca, with ESPN having access to the full ruling, which stated that Neymar was in breach of his contract as he terminated it prematurely without just cause "beyond his mere will" to sign for another club when PSG paid his release clause.
Neymar appealed the verdict but Barca now say all cases with their former player have been resolved.