Keila (German: Kegel) is a town and an urban municipality in Harju County in north-western Estonia, 25 km (16 mi) southwest of Tallinn. As of 2021, the town has a population of 10,499 inhabitants.

Keila is also the location of administrative buildings of the surrounding Keila Parish, a rural municipality separate from the town itself.

The oldest traces of human settlement in Keila trace back 2000 to 3000 years BC. Around 1000 years ago the village of Keila was established along the Keila river. In 1219 the Danish conquered Northern-Estonia and chose Keila as the site on which the Vomentakæ parochial Revala county church was to be built. The first church was a small wooden structure dedicated primarily to St. Michael which was replaced with a stone church at the end of the 13th century. Subsequently, the first written mention of Keila (Keikŋl) comes from Danish evaluation book writings in 1241.

In the 15th–16th century, a settlement comprising some tens of buildings and a hundred people formed around the church. At the same time the Livonian Order built a small fort south-east of the church on jõesaare (Known today as Jõepark). Ruins of the fort were first excavated in 1976 with continued finds up to 2007. During the Livonian War of 1558–1583 the settlement, including the church (Later restored in 1596), was destroyed. Further hampered by the plague and starvation in 1601–1602 the population decline reduced the community to a small church village. This was to be the case for three centuries.

An upturn began in the second half of the 20th century. One of the first notable cultural events was the erection of a statue of Martin Luther in 1862 near the kirikumõis (Church manor). However the statue was completely destroyed in 1949. In 1885 the first song festival was held in Keila. The festival was composed of 19 choirs and supervised by Konstantin Türnpu from Klooga. In 1867 the first school was opened in Väljaotsa farm celebrating the start of education in Keila. The development of Keila took a turn with the establishment of the Tallinn–Paldiski railway line in 1870. After the railway to Keila was built, the place became known—as a pun—as Kegelbahn (German for 'bowling alley').

Keila officially became a town on 1 May 1938.

During Soviet times a military base, known as Tankipolk 'Tank Regiment', was built on the outskirts of the town for the housing of soldiers and tanks. The base was demolished a few years after the Soviet army left the country. Years later a residential district was built on the site of the base. The woodland areas around it have also been cleaned up and turned into paved, and partially lit, paths. During winter the area acts as a skiing track with many hills and paths. The paths range from 3 to 7 kilometres (1.9 to 4.3 miles) in length. The largest of the hills is known as Tankimägi 'Tank Hill'. As of 2009^[update], no more than a few building foundations remain of the base.

The city is situated largely on a big hill known as Keila hill and on the valley of Keila River. On the westernmost side of Keila there is Niitvälja Bog.