Ban, whose arrival was confirmed by Iraqi state television and the UN’s official Twitter feed, was due to meet Nuri al-Maliki and Foreign Minister Hoshyar Zebari.
The talks were to concentrate on the situation in the Middle East and in particular the bloodshed in Syria, Maliki’s office said in a statement.
Ban was also due to give a news conference later on Monday.
His visit comes ahead of peace conference next week on the Syrian crisis in Switzerland dubbed “Geneva 2” which is aimed at engaging regime and opposition members in their first direct talks.
Talks held in Geneva in July 2012, involving world powers but no Syrian regime or rebel officials, concluded with an agreement that Assad and his opponents should decide on a transitional government whose representatives suited all sides.
Ban’s visit also comes as Iraq is embroiled in a bloody standoff between government forces and militants and anti-government tribes in Anbar province, the mostly-Sunni desert province in west Iraq which shares a long border with Syria.