Sir is a respectful form of address for a man, and a formal title used in the United Kingdom for knights and baronets.

Sir, SIR or SiR may also refer to:

Places

Iran

• Sir, Iran, Fars Province

• Sir, Razavi Khorasan

• Sir, West Azerbaijan

Palestine

• Sir, Jenin

• Sir, Tulkarm

Elsewhere

• Sir Creek, on the India–Pakistan border

• Sır Dam, Turkey

• Saskatchewan International Raceway, Canada

People

• Sir (singer), American singer, songwriter, record producer

• Jaroslav Šír (born 1923), Czechoslovak former skier

• József Sir (1912–1996), Hungarian sprinter

• Sedat Sir (born 1975), Turkish-Australian former Australian Rules footballer

Entertainment

• Sir (1993 film), a Bollywood film

• Sir (A Series of Unfortunate Events), a fictional character in A Series of Unfortunate Events

• Sir (album), by Fischerspooner

• Sir (2018 film), an Indian Hindi-language romantic drama film

• "Sir", a song by Nicki Minaj from Queen

• Sir (2024 film), an Indian Tamil-language action drama film

• Sir (2025 film), an Indian Odia-language drama film

Organizations

• Security Industry Registry, a corporate service provided by the New South Wales Police Force

• Sigma Iota Rho, a collegiate honour society for international studies

• Singapore Infantry Regiment, the main formation of the Singapore Army

• Society of Interventional Radiology, an American organization of health professionals

• Sons In Retirement, a fraternal organization of retired men

Science and technology

• SIR model, a compartmental model of the progress of an epidemic

• Secondary image registration, a type of passive autofocus in cameras

• Sequential Importance Resampling, a particle filtering algorithm

• Serial Infrared, the physical layer of the IrDA standard for data transmission

• Short interest ratio, a metric signalling prevailing investors' sentiment

• Signal-to-interference ratio, the ratio of useful signal versus co-channel interference received

• Silent information regulator protein involved in regulating gene expression

• Supplemental inflatable restraint or airbag, a vehicle safety device

Transportation

• Siantar railway station, Pematang Siantar, Indonesia

• South Indian Railway, an early Indian railway company

• Staten Island Railway, rapid transit line in the borough of Staten Island, New York, United States

• Surrey Iron Railway, a horse-drawn plateway that linked the former Surrey towns of Wandsworth and Croydon

• Sion Airport, the airport in Sion, Switzerland whose IATA code is SIR

Other uses

• Sirene (Sir in Serbian), a type of cheese

• Statutory Invention Registration, a publication of an invention by the United States Patent and Trademark Office

• Special Intensive Revision, an exercise undertaken by the Election Commission of India to prepare the voters list

See also

• Siir (disambiguation)