| SISO | Safe Inside Safe Outside 
| Others |
| SISO | Samsung Electronics India Software Operations
| Others |
| SISO | Samsung India Software Operations
| Others |
| SISO | Save Israel Stop the Occupation
| Others |
| SISO | Senior Information Security Officer
| Others |
| SISO | Serial In Serial Out
| Others |
| SISO | Settlement and Integration Services Organization
| Others |
| SISO | Sh*t In Sh*t Out
| Others |
| SISO | Shift In Shift Out
| Others |
| SISO | Sign in and Sod Off
| Others |
| SISO | Sign In Sod Off
| Others |
| SISO | Simulation Interoperability Standards Organization
| Others |
| SISO | Singapore Institution of Safety Officers
| Others |
| SISO | Single In Single Out
| Others |
| SISO | Single Input and Signal Output
| Others |
| SISO | Single Input And Single Output
| Others |
| SISO | Single Input Single Output
| Others |
| SISO | Single Input, Single Output
| Others |
| SISO | Single-Input and Single-Output
| Others |
| SISO | Slow Input, Slow Output
| Others |
| SISO | Society of Independent Show Organizers
| Others |
| SISO | Soft In Soft Out
| Others |
| SISO | Soft Input Soft Output
| Others |
| SISO | Soft-In Soft-Out
| Others |
| SISO | Soft-Input Soft-Output
| Others |
| SISO | Southern Illinois Symphony Orchestra
| Others |
| SISO | Spicy In Spicy Out
| Others |
| SISO | Strategy In Strategy Out
| Others |
| SISO | Students of Information Systems Organization
| Others |
| SISO | System Integrator and System Outsourcer
| Others |
| SISO | System Integrators and System Outsourcers
| Others |