Organ-on-a-chip (OOC) and multiorgan-on-a-chip (MOC) devices combine one or several cellular models with an engineered microenvironment. In the last 5 years, this technology has been demonstrated to improve cell resemblance with the in vivo situation to a level never reached before. Developing this platform can, therefore, be attractive to laboratories, but because this field combines two different fields of expertise, biology and engineering, it requires good project planning and excellent communication between people from the two fields. This chapter provides a guide for the thought process behind the development of an OOC or MOC platform to help laboratories construct their fit-for-purpose chip. This guide largely mirrors the rationale and developmental aspects used to develop a functional lung/liver-on-a-chip system in our laboratory, which will be used as a case study to assist readers in developing their chip.