We examine the impact of country-level generalized trust and civic cooperation (i.e., societal trust) on Big N auditor choice and audit fees. Because higher societal trust countries are associated with lower levels of agency problems, we expect a negative association between societal trust and Big N auditor choice and audit fees. We find this to be the case in countries with strong investor protection, i.e., a substitution effect. However, because higher trust societies may also experience higher costs of inappropriate behavior and place higher value on a strong audit function, we could observe a positive association between societal trust and Big N audit demand or audit fees. We find this to be the case in countries with weaker investor protection, i.e., a complementary effect. These results suggest that both formal institutions (audit, investor protection) and informal attitudes (trust, civic cooperation) can influence the demand and supply for audit services.