The story of “three strikes” sentencing provides an interesting example of simultaneous convergence and divergence in the arena of penal policymaking. The emergence of “three strikes” clearly includes some important “globalizing” elements that are consistent with the arguments put forth by some researchers. Such elements include the broader political and cultural conditions in both the United States and the United Kingdom that made the promotion of punitive policies appear politically attractive. Three strikes was a policy idea that first emerged in the United States and later appeared, in a more moderate form, in the United Kingdom. The policy content on both sides of the Atlantic was similar and the policy instruments displayed broad levels of similarity. However, there is limited evidence of direct policy transfer from the United States in this area. The United States influence seemed to be exerted more indirectly. The paper suggests that apparent convergence owed as much too similar shifts in underlying structural conditions and the politics of crime as it did to deliberate emulation of the United States. By undertaking detailed case histories of policy change, exploring both policy levels and processes, it is possible to begin to highlight and explain both convergence and divergence in penal policy. In recent years, several researchers have highlighted the international spread of penal policies that appear to have origins in the United States. Such developments include: zero tolerance, policing, youth curfews, the war on drugs, increased incarceration, and privatization of criminal justice agencies. Tables, references