As the designers and implementers of complex systems (such as websites, discovery tools, and knowledge repositories), we have great -- if sometimes unrealized -- power. And, as Stan Lee says, with great power comes great responsibility. In this presentation we will explore three key lessons in the ethics of systems design, and examine the practical implications of these lessons in the design of your own systems. We'll investigate how design choices can (intentionally or unintentionally) influence user behavior, reveal organizational priorities, and exacerbate or ease conflicts between your interests and those of your users. And we'll discuss how to be mindful of these considerations during the design process in order to ensure that your systems more effectively reflect your values, address your users' needs, and allow both your users and your organization to find success.