We examine whether public pressure related to compliance with subsidiary disclosure rules influences corporate tax behavior. ActionAid International, a non-profit activist group, levied public pressure on non-compliant U.K. firms in the FTSE 100 to comply with a rule requiring U.K. firms to disclose the location of all of their subsidiaries. We use this natural experiment to examine whether the public pressure led scrutinized firms to decrease tax avoidance and reduce the use of subsidiaries in tax haven countries relative to other firms in the FTSE 100 not affected by the public pressure. The evidence suggests that the public scrutiny sufficiently changed the costs and benefits of tax avoidance such that tax expense increased for scrutinized firms. The results suggest that public pressure from outside activist groups can exert a significant influence on the behavior of large publicly-traded firms. Our findings extend prior research that has had little success documenting an empirical relation between public crutiny of tax avoidance and firm behavior.