The article examines the impact of the Syrian crisis on the internal political situation in Lebanon. The analysis helps to reveal the fact that the activity of armed radical Islamist groups is enhancing in the country, which negatively affects the security of the population. The increase in the number of Syrian refugees alters the demographic situation, contributes to the deterioration of economic development indicators, to the increase of poverty, unemployment and street crime, as well as to the aggravation of social tension. Despite the efforts of the Lebanese government to maintain neutrality, the country is drawn into the Syrian conflict: the Shiite group Hezbollah is fighting on the side of Syrian President B. Assad, while Lebanese Sunni groups are helping the oppositional Free Syrian army. According to the author’s conclusion, despite the toughening of the struggle between the pro-Syrian and anti-Syrian blocs, centrist moods are growing in Lebanese society. They are related to the search for a compromise between the opposing sides.