The meeting tackled Lebanese developments, the official SPA news agency reported.
Hariri, for his part, posted his photo with the Saudi monarch on Twitter with a caption reading “I was honored today with visiting the Custodian of the Two Holy Mosques, King Salman bin Abdulaziz, at his office."
Monday’s meeting was attended by a host of Saudi officials, including Interior Minister Prince Abdulaziz bin Saud and Foreign Minister Adel al-Jubair.
Last week, Hariri tendered a surprise resignation during a televised address from Saudi Arabia.
In his speech, Hariri criticized Iran and its Lebanese ally Hezbollah, accusing Tehran of planting “sedition” and meddling in Arab affairs.
Hezbollah leader Hassan Nasrallah, for his part, said there was no reason for Hariri’s resignation, accusing Saudi Arabia of forcing the Lebanese premier to quit.
Hariri was appointed prime minister in late 2016, leading a 30-member government that included Hezbollah.