Mugrib al-Thanyan was executed in Eastern Province after being found guilty of shooting dead another Saudi after a dispute, the ministry of interior said in a statement.
His case brings to 110 the number of beheadings this year in the kingdom, which rights group Amnesty International says is one of the world's most prolific executioners.
The number of Saudis and foreigners put to death this year is up 126 per cent from 87 during the whole of 2014, according to AFP tallies.
The interior ministry has cited deterrence as a reason for carrying out the punishments.
Rights experts have raised concerns about the fairness of trials in the kingdom.