Proactive socialization tactics, measures that organizational newcomers take to facilitate their own adjustment, have been shown to predict adjustment and more distal work-related outcomes, such as organizational commitment and intent to remain with the organization. Several cognitions and behaviors are considered to be types of proactive socialization tactics, but research has yet to distinguish between different types. Also, several individual dispositions have been identified as antecedents of proactive socialization tactics, but there has been little focus on identifying contextual or non-dispositional individual difference antecedents. The purpose of this research was to propose a dual-mode conceptualization of proactive socialization tactics and to distinguish between tactics directed toward changing oneself and those directed toward changing one's environment. This research also examined the role of contextual factors, the newcomer's age, and the newcomer's work experience as antecedents of proactive socialization tactics. The results of this research suggest that job and workgroup characteristics do indeed play a role in predicting proactive socialization tactics. Age and work experience were predictors as well, but not as strong as expected. Both self-directed and environment-directed proactive socialization tactics predicted desirable adjustment outcomes, but self-directed tactics were clearly stronger predictors of these outcomes. There was some evidence to suggest that newcomers' early fit perceptions moderated relationships between antecedents, such as workgroup characteristics, and proactive socialization tactics. Theoretical and practical implications are discussed.