This research examines the effects of ethnic fractionalization and globalization on individual-level propensities toward generalized trust and cooperation at the national level. Conclusions regarding both ethnic-fractionalization and globalization remain mixed as to their influence on prosocial behavior. This chapter explores the relationship between these variables in Kenya, a country with an extremely heterogeneous population that has increased integration with the global economy over the past decade. Literate Kenyan male and female adults, ages 18 to 60, from two of Kenya’s largest ethnic groups, the Luo and Kikuyu, participated in an experimental public goods game in which players contribute to, and benefit from, a national account. Results are consistent with the argument that it is not ethnic fractionalization per se that is associated with lower cooperation but increased ethnic inequality. The implications of these findings are that trust and cooperation are highly contextually based and influenced by social and environmental factors.