一个多智能体系统（multi-agent system，缩写M.A.S.），是由一个在一个环境中交互的多个智能体组成的计算系统。多智能体系统也能被用在解决分离的智能体以及单层系统难以解决的问题。智能可以由一些方法，函数，过程，搜索算法或加强学习来实现。尽管存在相当大的重叠，然而一个多智能体系统并不总是一个基于智能体的模型（ABM）表现一致。ABM的目标是寻找遵循简单规则的智能体（这些智能体不需要体现出太强的“智能”）集体行为的解释，通常在自然系统又或者解决具体的工程问题。ABM的术语经常在学术界被运用，而MAS的术语经常在工程技术中运用。多主体系统的研究课题可以给予一个合适的视角去观察网络贸易，灾害应对以及社会结构建模。

A multi-agent system (M.A.S.) is a computerized system composed of multiple interacting intelligent agents within an environment. Multi-agent systems can be used to solve problems that are difficult or impossible for an individual agent or a monolithic system to solve. Intelligence may include some methodic, functional, procedural approach, algorithmic search or reinforcement learning. Although there is considerable overlap, a multi-agent system is not always the same as an agent-based model (ABM). The goal of an ABM is to search for explanatory insight into the collective behavior of agents (which don't necessarily need to be "intelligent") obeying simple rules, typically in natural systems, rather than in solving specific practical or engineering problems. The terminology of ABM tends to be used more often in the sciences, and MAS in engineering and technology. Topics where multi-agent systems research may deliver an appropriate approach include online trading, disaster response, and modelling social structures.