This study addresses a gap in the literature by examining interactions between parental monitoring and parental autonomy giving/personal autonomy in predicting changes in drinking behavior from high school to college. Using data from two unique studies (study 1 was 62.8% female, n = 425; study 2 was 59.9% female, n = 2245), we analyzed main effects of parental monitoring, parental autonomy-giving, and personal autonomy. We also analyzed interactions between parental monitoring and autonomy-giving, and between parental monitoring and personal autonomy. Analyses found significant main effects of parental monitoring on drinking, with high levels of parental monitoring protecting against heavy drinking. Personal autonomy was a protective factor in both high school and college, whereas parental autonomy-giving did not predict drinking behavior in either high school or during the transition to college. This calls into question the extent to which parental autonomy-giving is a primary influence on personal autonomy. Hypothesized interactions between parental monitoring and parental autonomy giving/personal autonomy were not statistically significant. In summary, parental monitoring seems to be protective in high school, and personal autonomy—but not parental autonomy-giving—is also protective. Whereas the latter finding is well established from previous studies, the protective effect of personal autonomy during the transition to college is a novel finding. This relationship suggests that efforts to identify sources of personal autonomy in early adulthood and methods for increasing autonomy may be warranted.