This dissertation is an empirical attempt to bridge and synthesize two distinct sets of theories in the sociology of development and the study of cross-national inequalities. Through this study, I gather data on three types of inequality (i.e., environmental, economic, and gender/political) observed between and within nations of the world and create panel datasets that track countries’ profiles over time. By using a growth curve modeling (GCM) approach, I study the trajectories of inequality and explain them by time-invariant contextual (local) and time-varying external (global) factors. This dissertation aims to contribute to the development of a more general and comprehensive framework for studying the observed trends of inequality in the last three decades by implementing a methodology that effectively incorporates theoretical elements from multiple schools of thought. By discovering the underlying trajectories and contributing factors to nations’ inequality trends, this dissertation implies several policy suggestions in the conclusion section that can benefit the international, national, and local actors and policymakers concerned with the overall well-being of societies and people in both developing and developed countries.