“Livability” has become a popular term in planning, design, and engineering circles, yet there continues to be a lack of clear consensus about what livability actually means, let alone how to measure it and how to achieve it. In response, this article draws deeply on the literature to develop a comprehensive understanding of this complex concept. The presented analysis suggests that livability is best understood as an individual's ability to access opportunities to improve his or her quality of life. However, one person's pursuit of quality of life can actually detract from the livability of another. This concept is particularly true in transportation, as one person's travel inherently touches the lives of others along the pathway. As wealth and social status often play a key role in determining whose pursuit of quality of life wins, a moral and ethical framework must be at the heart of the achievement of livability. Therefore, livability in a just society requires that all individuals be ensured equal access to such opportunities. Rather than one monolithic definition of livability, a need exists for a theoretical moral basis to measure, understand, and judge activities toward livability achievement through a set of clear, concise, and easily applicable livability ethics. Toward this goal, this paper first presents a comprehensive examination of the literature and then provides guidance to professionals on the application of livability concepts in practice by articulating (a) an overarching definition of livability and a set of supporting metaprinciples, (b) a set of ethical livability principles, and (c) a set of livability process principles.