Sir (disambiguation)

Sir is a respectful title for a man SIR or Sir may also refer to:

• Sir (A Series of Unfortunate Events), a Guardian character in A Series of Unfortunate Events
• Sampling Importance Resampling
• Saskatchewan International Raceway, a Saskatoon drag strip
• Security Industry Registry
• Sigma Iota Rho
• Signal-to-Interference Ratio
• Singapore Infantry Regiment
• Society for Individual Rights, a defunct homophile organization
• Society of Interventional Radiology
• Sons In Retirement (SIR)
• Staten Island Railway
• Statutory Invention Registration
• Surface insulation resistance
• Surrey Iron Railway
• Sir, Iran, a city in Fars Province
• Sirene (Sir in Serbian), a type of cheese
• Sir (film), a 1993 Bollywood film
• The SIR model, one of the compartmental models in epidemiology
• The Sir. Community, a gaming and machinima group from the Battlefield games series.
• Serial Infrared, a category of Infrared Data Association
• Secondary Image Registration, a type of passive autofocus
• Supplemental Inflatable Restraint or airbag