In this paper, ethics is discussed in relation to system dynamics. The domain of ethics is very broad which is why we will first of all demarcate what is meant by ethics here. Then, we will discuss the importance of ethics for the domain of system dynamics and where it could come into play. Calls for, mentions of, and applications of ethics in the system dynamics literature will then be reviewed, followed by a discussion of possible contributions of the explicit consideration of ethics to the domain of system dynamics and of system dynamics to the domain of ethics. Two examples will be discussed: ’responsibility’ and ’sustainable development’. Then, some advantages and disadvantages of combining ethics and system dynamics will be discussed. And finally, possible ways to deal with ethics in system dynamics will furthermore be proposed in the concluding section.