| MLSS | mixed liquor suspended solids | 混合液悬浮固体 |
| MLSS | Multiple Level Security System | 多级安全系统 |
| MLSS | Mailing List Subscriber Services | 邮件列表订阅服务 |
| MLSS | mixed liquor suspended solid | 混合液悬浮固体 |
| MLSS | Multilevel Secure Server | 多级安全服务器 |
| MLSS | Maximal Lactate Steady State | 最大乳酸稳态 |
| MLSS | Mixed Liquor Suspended Solids (environmental waste) | 混合液悬浮固体（环境废物） |
| MLSS | Ministry of Labor and Social Security (China) | 劳动和社会保障部（中国） |