The European Commission is often considered the motor of European integration. This chapter assesses the Commission’s specific role in the area of justice and home affairs (JHA) and compares it to findings from the literature on the European Commission more generally. It focuses on a number of pivotal questions on the role of the Commission in JHA. The chapter analyzes how influential the Commission is in the area of JHA as compared to the other European Union (EU) institutions and to what extent it was able to leave a mark on EU legislation in the field. It investigates how the competences of the Commission in this policy area have changed over time and compares competences across the individual subfields of JHA, including cooperation in judicial matters, police cooperation, and immigration and asylum policies. The chapter assesses the positions advanced by the Commission in the area of JHA and compares them to those proposed by the other EU institutions.