Rotating Service Structure, used in the Space Shuttle program launches

Range Safety System, used in the Space Shuttle Solid Rocket Booster and other systems

Rashtriya Swayamsevak Sangh, a Hindu nationalist organization in India.

RSS (file format), Really Simple Syndication, Rich Site Summary or RDF Site Summary, several similar forms of web syndication used by news websites and weblogs

Repetitive strain injury, also Repetitive stress syndrome, an overuse syndrome

Roland Sound Space by Roland Corporation

Russell-Silver syndrome

RSS is a three-letter abbreviation that can stand for a wide variety of terms.

Rochester Subway, which had the AAR reporting mark, RSS

Rockdale, Sandow and Southern Railroad, which currently has the AAR reporting mark RSS

Regional Spatial Strategy provides a regional level planning framework for the regions of England

Royal Statistical Society, the main professional body for statisticians in the UK

Road Sensing Suspension, a part of the Northstar System brand of General Motors automotive technology

Residual sum of squares, in regression models

Radio Service Software, a proprietary suite of programs sold by Motorola

Root-sum-square, the square root of the sum of the squares of the elements of a data set. To perform this operation, which is called "taking the RSS": square each of the elements, add up the results, and take the square root of the total. Used colloquially to refer to the magnitude of a vector. Compare this to root mean square.

Reduced Space Symbology, the former name of GS1 DataBar, an approved barcode of GS1

Regional Security System, an agreement between several countries situated in the Eastern Caribbean region. The RSS acts as a unit made up of a series of defence and disaster management forces.

Red Swastika School, Singapore

Riverside Secondary School, Windsor, Ontario, Canada