Trade unions
S
| Full Name | Short Name | Notes |
|---|---|---|
| Scottish Horse & Motormen's Association | SHMA | |
| Scottish Miners' Association | SMA | |
| Scottish Miners' Federation | SMF | |
| Scottish Miners National Union | SMNU | |
| Scottish Mineworkers' Association | SMWA | |
| Scottish Painters Society | SPS | |
| Scottish Prison Officers' Association | SPOA | |
| Scottish Union of Power-Loom Overlookers | SUPLO | |
| Ship Constructors and Shipwrights' Association | SCSA | |
| Shop Assistants' Union | SAU | |
| Social Democratic Federation | SDF | |
| Society of Chiropodists and Podiatrists | SCP | |
| Society of Civil Servants | SCS | |
| Society of Graphical and Allied Trades | SOGAT | merged with NGA in 1991 to form GPMU |
| Society of Radiographers | SoR | |
| South Wales Miners Federation | SWMF | |
| Staff Tutors' Association | STA |