Is it joint democracy or state similarity that has a pacifying impact on interstate relations? This study explores the complementarity of the two propositions and demonstrates the potential of a particular kind of shared emancipative culture embracing values of autonomy, equality, choice, and voice to amplify the impact of joint democracy on interstate conflict. The data on cultural values, which comes from the World Values Survey, was integrated with the data from the Correlates of War Project to test the impact of joint democracy and cultural similarity on militarised interstate disputes (1981–2010). We find that culturally similar dyads are less likely to be involved in conflict with each other than culturally dissimilar dyads. Although, cultural similarity does not wash out the pacifying effect of democracy, it offers a complementary explanation to the democratic peace. We also find that states that are democratic and share higher than average scores on the emancipative values are less likely to engage in militarised interstate disputes than democratic states, which are culturally dissimilar or score low on the emancipative dimensions. This provides support for an additional normative/cultural impact on democratic peace.