This thesis consists of two studies examining early medieval locks and keys as socially active and agentive objects. The first presents evidence for the continued use of locks and keys through the early Middle Ages in England. Locks are among the most complex objects manufactured in this period, requiring specialised knowledge and skill. Their continued use suggests that there was a perceived need amongst communities for these objects and that there was also an available network of craft workers who could supply that need. This is particularly important for understanding the nature of that network during the periods of change and transition in early medieval England. The second study looks at the social significance of locks and keys by focusing on the Viking Age site of Birka. It challenges the traditional interpretation of keys used as grave goods as primarily and simply signalling female status. Instead evidence is presented for these objects carrying multiple meanings and having multiple uses and intentions within grave assemblages. Recognising this complexity allows the opportunity to see the relationship between women and keys with greater nuance, and also to explore how these objects may have been used to help navigate and control the relationship between the living world and the world of the dead.