Substantial theoretical and empirical attention has been directed at isolating the structural conditions that lead to shifts in the size of metropolitan police departments in the United States. These studies rely heavily on ethnic and racial threat explanations, which imply that larger police forces will be employed in jurisdictions with larger minority populations. It is entirely unclear, though, whether such accounts are applicable outside the United States. This study fills this void in the literature by assessing the extent to which ethnic threat hypotheses can explain variations in police strength using data on 40 large Canadian cities from 1996 to 2006. Results show that the size of the minority population significantly influences the size of metropolitan police departments.