Toompea (from German: Domberg, "Cathedral Hill") is a hill in the central part of Tallinn, the capital city of Estonia. The hill has an area of 7 hectares (17 acres) and is about 20–30 metres higher than the surrounding areas. Toompea is part of the medieval Tallinn Old Town, a UNESCO World Heritage Site.

Toompea is the site of the Government of Estonia and the Riigikogu (parliament), both of which are often simply referred to as Toompea. The parliament meets in the Toompea Castle which is situated in the southwestern corner of the hill and topped by the Pikk Hermann ("Tall Hermann") tower. The flag on the top of the tower is one of the best-known symbols in Estonia of the government in force.

Toompea first emerged as an island from the Baltic Ice Lake around 10,000 years ago. Due to steady post-glacial rebound it became connected with the mainland during the early Littorina Sea stage. At 5,000 BCE the sea still reached the foot of the cliffs of Toompea. The modern coastline is at a distance of more than 1 km from Toompea and the foot of the hill lies at 17–20 m above sea level. The hill reaches about 48 metres (157 ft) in elevation.