OBJECTIVE To develop and validate a Burden Transfer Inventory (BTI) of stressful client behaviors and to evaluate whether those behaviors are associated with client caregiver burden and contribute to veterinarian stress and burnout. DESIGN 3-stage cross-sectional psychometric validation study. SAMPLE 1,151 small animal veterinarians and 372 dog and cat owners. PROCEDURES During stage 1, a pool of 34 items representing stressful client behaviors was created through open-ended surveys of practicing veterinarians and 3 phases of pilot testing. During stage 2, 1,151 veterinarians recruited through the Veterinary Information Network completed a survey including those behavior items and validated measures of stress and burnout. Completed surveys were randomly assigned to either a measure development or validation database for factor and item analyses. Data were then combined to determine whether the BTI was correlated with measures of stress and burnout. During stage 3, owners of dogs and cats with a serious illness completed an online survey to assess how frequently they engaged in each BTI item as well as a validated measure of caregiver burden. RESULTS For dog and cat owners, there was a significant positive correlation between caregiver burden and the frequency that those owners reported engaging in BTI items. The frequency that veterinarians reported encountering BTI items was positively correlated with measures of stress and burnout, which suggested burden transfer from owners to veterinarians. The extent to which veterinarians reported being bothered by BTI items was a more robust predictor of stress and burnout than the frequency with which those items occurred. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated the BTI can be used to understand how client behaviors associated with caregiver burden affect veterinarian stress and burnout. The BTI may be useful to identify specific stressors affecting individual veterinarians and how they react to those stressors.