Online dispute resolution (ODR) services are e-justice service conduits that utilize, implicitly or explicitly, electronic negotiation systems. They are a key mechanism that may provide a viable solution to the flood of e-disputes, and even for face-to-face disputes that can be resolved without being colocated (e.g., see how courts resolve cases during the COVID-19 pandemic). Justice is important in negotiation processes. It is therefore suggested that ODR services are a viable means to serve justice on the web. In this chapter, we describe the state of e-justice and introduce the need for ODR services. We then present the concept of ODR, its different forms, and its association with negotiation support systems. To this end, we portray a classification of ODR services, give examples of different types of services, and specifically discuss one of the promising types, namely, principle-based dispute resolution services. The chapter concludes with