LSS can refer to:
- The Lithic Studies Society
- Langstaff Secondary School, in Richmond Hill, Ontario
- large-scale structure of the universe
- XM26 Lightweight Shotgun System
- Lawrence Sheriff School, a grammar school located in Rugby, Warwickshire.
- Lone Star Showdown, the official rivalry between the Texas A&M Aggies and the Texas Longhorns
- Lone Star Steel Company, a tubular steel mill in Lone Star, Texas
- Lunds StudentsÄngförening, a Swedish male-voice choir
- Life Saving Society
- Lincoln Square Synagogue
- LSS Data Systems, a medical software company
- Lumbar spinal stenosis, a medical condition in which the spinal canal narrows
- Lean Six Sigma, a synergized managerial concept of Lean manufacturing and Six Sigma