The Assertion Inventory (AI) (Gambrill & Richey, 1975), a 40‐item questionnaire, collects two types of information about assertive behavior: (a) degree of discomfort felt in specific situations; and (b) judged probability of engaging in a behavior. Ss are categorized into one of four groups: Assertive (low discomfort and high assertion), Unassertive (high discomfort and low assertion), Doesn't Care (low discomfort and low assertion), or Anxious Performer (high discomfort and high assertion). The purpose of the study was to validate the Al using a role‐play format. Two experiments comprised the study. The Ss were 96 undergraduates (48 in Experiment 1 and 48 in Experiment 2). The AI scores were maximally representative of each Al category. The results of experiment 1 were congruent with inventory scores; the results of Experiment 2 were not. Potential consequences of social desirability and the use of role‐play as an outcome measure are discussed.