The primary aim of this article is to test a process model of request tactic evaluation in two different cultures. It examines possible links between the perceptions of interactive constraints (concern for clarity, concern for avoiding hurting the hearer's feelings, concern for nonimposition, concern for avoiding negative evaluation by the hearer, concern for effectiveness), and likelihood of using specific tactics. Theory and research drawn from the areas of communication competence, conversational goals, and requesting behaviors were used to formulate a causal model of request tactic evaluation. Data to test the proposed model were drawn from undergraduates studying in Korea (N = 296) and the U.S. (TV = 299). The results indicated that in both cultures, perceived effectiveness functions as a mediating variable between the four interactive constraints and perceived likelihood of use. Among Korean participants, two social-relational constraints (concern for avoiding negative evaluation by the hearer, and concern for avoiding hurting the other's feelings) substantially contribute to the prediction of effectiveness. On the other hand, among the U.S. participants, clarity was an extremely strong predictor of perceived effectiveness of tactics. Perceived effectiveness played an equally important role in the prediction of likelihood of use in both cultures. The implications of the model for theory and practice are discussed.