• outsourcing;
  • opportunism;
  • contractual governance;
  • relational governance;
  • culture

To address concerns of opportunism, outsourcing firms are encouraged to deploy contractual and relational governance. The individual and collective effects of these mechanisms have been previously examined but not in specific contexts. This study examines the effects of contractual and relational governance on provider opportunism, incorporating the moderating influence of a “shift parameter”—national culture. Our results reveal that contractual governance is more effective in individualistic and low uncertainty avoidance cultures. Relational governance is more effective in collectivist and high uncertainty avoidance societies. The individualism–collectivism dimension also moderates the joint effect of these mechanisms. While the mechanisms are generally complementary in mitigating opportunism, a singular focus on either contractual or relational can be just as effective under situations of high individualism and collectivism, respectively. Copyright © 2014 John Wiley & Sons, Ltd.