Aoun, an ally of Hezbollah, will discuss many issues in Riyadh, including aid to the Lebanese army and travel warnings to Lebanon.
Lebanon's president, Michel Aoun, flew to Saudi Arabia on Monday on his first visit abroad since his October election, which he won with the support of Riyadh's arch-foe Hezbollah.
Aoun's trip, part of a tour that will also take him to Qatar and Iran, will seek to lift travel advisories imposed by some Gulf states last year on nationals visiting Lebanon, which severely damaged its tourism sector.
Lebanon is caught up in a regional rivalry between Saudi Arabia and Iran. Riyadh appeared to disengage from Lebanon over the past year in response to perceived snubs by Beirut in the struggles against Iran in Syria, Yemen, Iraq and Bahrain.
In February, Riyadh cancelled a $3bn aid package for the Lebanese army and also advised big-spending Saudis not to visit Lebanon, which relies heavily on tourism.
Riyadh was irked by Lebanon's refusal to condemn attacks on the Saudi embassy in Tehran, after the execution of Saudi Shia dissident Sheikh Nimr al-Nimr.