| SEIU | Secondary Education Interdisciplinary Unit | 中等教育跨学科股 |
| SEIU | Special Education Intake Unit | 特殊教育招生组 |
| SEIU | Screw The Employees International Union | 拧员工国际联盟 |
| SEIU | Strategic Equipment Systems Incorporated | 战略装备系统公司 |
| SEIU | Software Engineering Institute Union | 软件工程学会联合会 |
| SEIU | Service Employees International Union | 服务员工国际联盟 |