Social psychologists have long recognized that attitudes can powerfully influence our perceptions, cognitions, and actions, profoundly shaping virtually all aspects of social behavior.  Equally clear, however, is that attitudes do not always do so, and attitude researchers have made great strides in recent years toward identifying the particular features of attitudes that govern their durability and impactfulness.  The current research expands on these recent advances by exploring features of the social environment in which attitude holders are situated and tracing the implications of these contextual features for attitude properties and processes.  In particular, this work focuses on the composition of the “social networks” in which people are embedded, or the webs of interpersonal relationships that link individuals to others in their social environment. I will present both experimental and correlational evidence regarding the impact of social network composition on the durability of people’s attitudes, and the psychological mechanisms through which features of social networks may affect individual-level attitude strength.