The Rosemary's Baby star is travelling to the Wadi Khaled and Beqaa Valley regions, which are near the Syrian border, during her visit.
She is due to speak with host families and refugees, visit UNICEF-supported child counselling centres, and distribute warm winter clothing to the needy.
After her first meetings on Monday, Farrow tweeted: "Today was an unbroken chain of stories - stories of loss, grief, deprivation, frustration and always the longing to go home. (They told me,) 'We want to go home and above all, we want peace.'"
Farrow has also appealed for increased international assistance for those who have escaped Syria amid ongoing fighting between rebel forces and government troops.