Summernats (a portmanteau of "Summer" and "National"), is an annual car festival held in Canberra, Australia since 1987, except 2021. Summernats, which is usually held at the start of the year, is the best known specialist car enthusiast festival in Australia, and an event which attracts many tourists to Canberra, bringing in excess of $20 million in economic benefit to the ACT economy. It has increasingly been promoted as an event for families.
 The Summernats spectator attendance record was set in 2017, with 119,184 attendees. Summernats is held over a four-day period, with many events, with prizes in competitions such as for burnouts, parades of cars around the track, fireworks at night and two outdoor concerts held on Friday and Saturday nights. The festival features many vehicles with airbrushed artwork, and restored and modified cars.
 The first Summernats was held on 31 December 1987.
 Between 1987 and 2009, Summernats' promoter and organiser was Chic Henry. Henry sold Summernats in 2009 to a new company called Summernats Pty Ltd. The naming rights sponsor of Summernats is Street Machine magazine, and the presenting sponsor is Rare Spares.
 The ACT Government has expressed its strong support of Summernats, praising the significant benefit it brings to Canberra's economy.
 The Summernats spectator attendance record was set in 2017 with 119,184 attendees.
 Summernats is held at Exhibition Park in Canberra (EPIC), corner of Flemington Road and Federal Highway, Lyneham. In 2022, during Summernats 34, the burnout pad grandstand was officially named in honour of Summernats founder Chic Henry.
 Summernats 34, which was due to take place in January 2021, is delayed until January 2022 due to EPIC being used by ACT Health as a COVID-19 testing facility until at least the end of November 2021. A new, reduced capacity, 5,000 maximum versus the usual ~100,000 attendance, "Summernats Rev Rock ‘n’ Roll" festival was planned to run over the 5–7 March 2021 Canberra Day long weekend to tide fans of the car festival over. However on 13 January 2021, this new event was also cancelled.
 Many awards are given during the course of the festival.
 The most prestigious award is the "Summernats Grand Champion".
 The Grand Champion award was introduced at Summernats 6 - with Peter Fitzpatrick being the first recipient (the first of Peter's six Grand Champion awards). Prior to this the top award was; Top Street Machine Overall.
 The Summernats holds one of Australia's most prestigious Show and Shine events. Vehicles from around the nation use the Summernats to announce their arrival on the Australian scene. There are the following categories:
 In addition, there are some awards that are highly coveted amongst the Australian vehicle modifying community:
 Custom Air brushing is also celebrated at the Summernats, where an exhibition occurs in the Meguiar's Pavilion.
 There is a multitude of awards handed out to entrants in cars, which are in the following categories:
 In this competition cars are bolted to a device that measures horsepower at the wheel hubs. During the course of the Summernats, many awards in different categories are handed out in the 'Dyno-cell' and power readings of over 3000 hp at the wheels have been registered.
 Summernats Horsepower Heroes Results:
 9  - 1996 Anthony Fabris VL Walkinshaw 325rwhp
 10 - 1997 Matt Bunton HQ 454 Van 372rwph
 11 - 1998 Jason Gray HSV GTS 404rwhp
 12 - 1999 Jason Gray HSV GTS 486rwhp
 13 - 2000 Rob Vickery VS Commodore Ute 527rwhp
 14 - 2001 Todd Wilkes Giocattolo 850rwhp
 15 - 2002 Rob Vickery VS Commodore Ute 1023rwhp
 16 - 2003 Eddy Tassone VH Commodore 1376rwhp
 17 - 2004 Brett Waine VH Commodore 1470rwhp
 18 - 2005 Eddy Tassone VH Commodore 1259whp
 19 - 2006 Craig Munro, TRYHRD VX HSV Clubsport 1262rwhp
 20 - 2007 Trick & Mansweto, Ford Capri 940rwhp
 21 - 2008 Craig Munro, TRYHRD VX HSV Clubsport 1895rwhp
 22 - 2009 Lyle Lemon MRPSI, 1533rwhp
 23 - 2010 Adrian Abella, FPV Typhoon 869rwhp
 24 - Graham Longhurst, HZ Holden 891rwhp
 25 - Jake Edwards, Torana, 1592rwhp
 26 - 2013 Jake Edwards, Torana, 1666rwhp
 27 - 2014 Michael Daniels, Falcon XR6 Turbo 1131rwhp
 28 - 2015 Jake Edwards, 2084rwhp (qualifying)
 29 - 2016 Jake Edwards, 1783rwhp
 30 - 2017 Jake Edwards, 1663rwhp
 31 - 2018 Paul Allen, 1010 hp
 32 - 2019 Brenden Medlin, 2483 hp
 33 - 2020 Maria Passos, 2202 hp
 35 - 2023 Cody Hunt,  1643rwhp
 A crash at Summernats 2006 injured a number of people (various sources indicating four, five or six).
 Street cruises were stopped after the 2005 Summernats, following crowd control issues, however thanks to the support of the ACT Government and several years of exemplary crowd and entrant behaviour the City Cruise was re-introduced in 2014. The City Cruise is the first driving event at each Summernats and was limited to 300 entrant vehicles, however this was recently raised to 400.
However Summernats spokesman Chic Henry was quoted as saying "The situation could be compared to so many other situations in life where people may have been having a bit too much fun, maybe having a bit too much alcohol."
 In 2008 and 2011 mobs of men allegedly sexually harassed female patrons. In 2017 the promoters adopted a zero tolerance policy to harassment. The festival has experienced frequent complaints and allegations of sexual harassment and other violence towards women by participants, including having a history of women being shouted at to 'take your top off', and men holding placards that read "tits out for the boys".
 In 2008, a mob of up to 400 men was observed by journalists surrounding and harassing women, leading Australian Federal Sex Discrimination Commissioner Elizabeth Broderick to comment that such conduct fosters an environment that may lead to rape. Security staff were described as "powerless" to stop the mob, although event organiser Chic Henry stated that he was happy with the performance of security.
 In 2011, another mob was alleged to have occurred.
 In 2017, Summernats announced its zero-tolerance approach to sexual harassment.