This article examines democratization as an aspect of human development where: human development is meant to proceed as people attain greater autonomous choice in shaping their lives. Democratization promotes this process in so far as it institutionalizes freedom of choice based on civil and political liberties. This perspective allows one to integrate modernization-based explanations and civic culture-based explanations of democratization under a common theoretical umbrella. For both types of explanations reflect aspects of human development. Modernization provides human resources that increase people's capabilities to act in accordance with their autonomous choices; and the rise of a civic culture promotes liberty aspirations that increase people's emphasis on autonomous choices. Linked through their common focus on autonomous human choice, human resources and liberty aspirations provide overlapping sources of pressure for the growth of freedom. Within the limits set by the extent to which freedom is not yet present, human resources and liberty aspirations are conducive to the growth of political freedom in interchangeable ways. These hypotheses are tested against the massive wave of democratization processes that occurred from the 1980s to the 1990s, using data from 62 nations of the WorldValuesSurveys. We find that democratization is driven by social forces that focus on the growth of autonomous human choice, reflecting human development. From this perspective, modernization-based and civic culture-based explanations of democratization are manifestations of the same theme: the expansion of autonomous human choice.