Prime Minister is also due to hold talks with powerful Crown Prince Mohammed bin Salman
Lebanese Prime Minister Saad Hariri met Saudi King Salman on Wednesday, in his first visit back to the country since his resignation in the kingdom sparked a crisis between the longtime allies.
Hariri announced on November 4 that he was stepping down in a televised address from Riyadh, only to rescind it the following month after France intervened.
The shock resignation had stirred tensions between Riyadh and Beirut, amid suspicions he had been placed under house arrest.
Saudi Arabia's state news agency SPA said Hariri and King Salman discussed "bilateral relations and recent developments in Lebanon".
It publishing pictures of the two leaders locked in a firm handshake.
He is also due to hold talks with powerful Crown Prince Mohammed bin Salman, whose impact on the kingdom's policies has steadily expanded since his appointment as heir to the throne in June.
His visit comes after a meeting Monday in Beirut with Saudi envoy Nizar al-Alula during which Hariri said he received and accepted an invitation to travel to Riyadh.
Alula also met with President Michel Aoun, who told him of Lebanon's desire to "maintain the best relations" with the oil-rich Gulf state.
Relations between the two countries have been strained by the competing influences in Lebanon of regional rivals Saudi Arabia and Iran.
Lebanon will hold legislative elections on May 6, the country's first since 2009.