While electoral mobilisation for ethnic votes is commonplace in modern democracies, the conditions under which political elites make ethnic appeals to voters during elections remain underexplored in the literature. To fill this gap, this chapter identifies several political and economic determinants, including electoral competitiveness, political institutions, information shortages, and economic inequalities between and within ethnic groups, that incentivise political elites to use ethnic issues to mobilise voters and secure electoral gains. Using cross-national data on party platforms, covering 386 parties across 27 democracies, consistent evidence is found that ethnic mobilisation intensifies when economic inequality between ethnic groups is high and economic inequality within ethnic groups is low. Meanwhile, no evidence is found that other factors affect ethnic appeals. The results advance our understanding of the relationship between economic inequality and ethnic mobilisation while also encouraging policymakers to minimise the negative consequences of ethnic politics in ethnically divided societies.