多用户操作系统允许多个用户在同一时间内使用计算机。最明显的一个例子是远程登录服务器，多个远程用户有权在同一时刻进入Unix Shell系统。

Multi-user software is software that allows access by multiple users of a computer. Time-sharing systems are multi-user systems. Most batch processing systems for mainframe computers may also be considered "multi-user", to avoid leaving the CPU idle while it waits for I/O operations to complete. However, the term "multitasking" is more common in this context.