Kifisia or Kifissia (also Kephisia or Cephissia; Greek: Κηφισιά, pronounced [cifiˈsça]) is a municipality and one of the most affluent northern suburbs in the Athens agglomeration, Attica, Greece, mainly accessed via Kifissias Avenue, running all the way from central Athens up to Theseos Avenue in the suburb of Nea Erythraia. It has traditionally been home to rich Greek families and major Greek political families.

The municipality Kifisia was formed during the 2011 local government reform by the merger of the following 3 former municipalities, that became municipal units:

• Ekali
• Kifisia
• Nea Erythraia

The municipality has an area of 35.100 km, the municipal unit 25.937 km.

Kifisia is situated in central Attica, at the western end of the forested Penteli mountain range. The small river Kifisos forms the western border of the municipality. Kifisia is situated 12 km northeast of Athens city centre. The built-up area of Kifisia is continuous with those of the neighbouring suburbs Lykovrysi, Nea Erythraia, Marousi and Pefki. Kifisia consists of the following neighbourhoods: Adames, Ano Kifisia, Kato Kifisia, Kefalari, Nea Kifisia and Politeia (or Politia). It is a green suburb with many parks and tree-lined streets.

The main thoroughfare is Kifisias Avenue, which connects Kifisia with central Athens and the A6 toll motorway. The Kifisia station is the north terminus of Athens Metro Line 1.

Kifisia has a hot-summer Mediterranean climate (Csa) with hot, dry summers and cool, rainy winters. Owing to its higher elevation, Kifisia, like most of the northern part of Athens, has a significantly lower mean annual temperature than the center and the coastal parts of the city (16.1 °C) according to the 1956-2010 annual average of the adjacent weather station of Tatoi, though this has slightly increased in recent years.

Yearly precipitation totals around 450 mm, one of the highest values for the whole Athens basin, mostly due to the higher amounts of precipitation received caused by lake-effect rain or snow from the Aegean Sea to the north-east in the winter months and the somewhat more frequent occasional summer thunderstorms, when compared to the rest of the city. Snow in particular, though not excessively common, can cause heavy disruption to daily life as it occasionally falls in large amounts during short periods. Notably, snow accumulation had reached 80 cm during a severe snowstorm on 4–6 January 2002.

Cephisia was a deme of ancient Athens. It was the home of the famous dramatist Menander (circa 342-291 BC). Cephisia had become a famous retreat of philosophers during the reign of the Roman emperor Hadrian, when the wealthy Herodes Atticus of Marathon, Greece built the Villa Cephisia. In his Attic Nights, Aulus Gellius describes the unique ambiance of intellectual ferment and aristocratic leisure in an idyllic setting which he created there. It was also the practice of Herodes to provide free instruction in philosophy for selected youths from Athens. The remains of some of his family funeral monuments lie at the centre of the town in Platonas Square. He also beautified a sanctuary to the Nymphs in the ravine of Kokkinara, in the nearby district of Kefalari.

The history of Kifisia during the medieval period is obscure, but the remains of a monastery church dedicated to the Virgin of the Swallow (Panagia Chelidonas) is associated with a story about a battle fought there between local people and unspecified "invaders". This chapel is a rare example of a monastery church originally provided with a fireplace, for the chimney remains.

During Ottoman period, in 1667, Kifisia was visited by the Turkish traveler Evliya Çelebi. He described a small country town set in a fertile plain of paradisaic beauty, with three hundred tile-roofed houses. Half the inhabitants of the town were Muslims and half were Christians. He records that there was a single mosque, without a minaret, and many small Christian chapels - some of which survive today.

The temperature in Kifisia tends to be significantly lower than that of the city, so following the independence of Greece, it quickly became a summer resort of the ruling class of the new state.

The village was home to an Arvanitika speaking community, however due to its proximity to Athens, it has undergone a language shift. The popularity of Kifissia faded somewhat during the middle of the nineteenth century when the danger of raids by brigands who infested the nearby mountains was very real. However, the suppression of brigandage, and the arrival of the railway in 1885, led to the dramatic development of the area.

It became the fashion for wealthy Athenian families to build summer houses in Kifisia, and keen social competition led to the creation of a unique architectural ambiance, as villas in ever more exotic styles proliferated. For those unable to afford a summer house, many hotels were built, where the slightly less affluent could spend the holiday months rubbing shoulders with their social betters.

The heyday of Kifisia was probably during the inter-war period, when the leaders of the two main rival political parties frequented different hotels in the town together with their most important supporters.

Following the liberation of Greece from German occupation in 1944, the British Royal Air Force ill-advisedly made its headquarters in Kefalari, taking over several hotels. With the outbreak of the Greek Civil War, the RAF personnel were first besieged, then forced to surrender, and marched across the mountains into northern Greece; being released in Trikala only after a truce had been arranged.

The Goulandris Museum of Natural History is situated in the heart of Kifissia and has collections from the natural wildlife of the Greek territory.

Accenture, Aegean Airlines, Barcleys, BP, Eurobank Ergasias, Eltrak, Ellaktor, Kioleides, Ferrari Metaxa, Metro S.A., Volvo and others have their head office in Kifisia.

Kifissia has several sport clubs in different sports. From them, most notable are ZAON, club with many Panhellenic titles in Greek women volleyball, Kifissia AC that plays almost constantly in men volleyball first division (A1 Ethniki) and Nea Kifissia B.C. that plays in basketball first division (Greek Basket League). The football team of Kifissia is Kifissia F.C., and plays in Super League Greece (top division). Kifissia also is the seat of Athina 90 (most times winner in Futsal League), AOH Hymettus (most times winner in Field Hockey League), and Iraklis Kifissias Presence in A1 Womans Category, with more than 200 athletes in Iraklis Kifissias Volleyball Academy.

Sport clubs based in Kifissia
Club	Founded	Sports	Achievements
Kifissia AC	1932	Volleyball	Presence in A1 Ethniki
Kifissia F.C. (Former: AO Kifissia, Elpidoforos)	2012 (1932) (1971)	Football	Presence in the Super League Greece
Iraklis Kifissias	1992	Volleyball	Presence in A1 Womans Category, with more than 200 athletes in Iraklis Kifissias Academy
ZAON Kifissia	1966	Volleyball, Basketball	Panhellenic titles in women volleyball
Athina 90	1990	Futsal	Panhellenic titles in Futsal
AOH Hymettus	1990	Field Hockey	Panhellenic titles in Field Hockey
Nea Kifissia B.C.	1996	Basketball	Presence in A1 Ethniki

The population grew fast between 1991-2001 by 18,3% while in 2001-2011 the percentage was lower, 7.13%

Year	Municipal unit	Municipality
1951	12,991	-
1981	31,876	-
1991	39,166	-
2001	43,929	-
2011	47,332	70,600
2021	48,700	72,878

• Menander (circa 342-291 BC), dramatist, born in Kifisia
• Emmanuel Benakis, merchant and politician, died in Kifisia
• Andreas Empeirikos (1901 in Romania - August 3, 1975), poet, died in Kifisia
• Penelope Delta (1874 Alexandria – 27 April 1941)
• Theodoros Pangalos (1878–1952), general, died in Kifisia
• Themistoklis Sophoulis (1860–1949), politician, died in Kifisia
• Ioannis Metaxas (12 April 1871 – 29 January 1941), politician and major general of the Hellenic Army, died in Kifisia
• Evgenios Spatharis (1924–2009), shadow theatre artist, born in Kifisia
• Antonis Samaras (born 1951), politician and grandson of Penelope Delta

• Official website (in Greek)