This study examined the joint and independent effects of experimentally manipulated social contexts and individual differences in hostility and perceived social support on physiological responses to a social stressor, while illustrating the use of the interpersonal circumplex for integrative social psychophysiological research. Undergraduate women completed a speech task in a supportive, neutral, or provoking context and completed measures of hostility and perceived social support. The provoking context evoked the largest blood pressure and heart rate (HR) responses, followed by the neutral and the supportive context. Social context also influenced HR and electrodermal reactivity during task preparation. Hostility elicited higher systolic blood pressure (SBP) reactivity during preparation, speech, and recovery. Perceived social support interacted with context to affect SBP and HR during speech and preparation. The roles of interpersonal characteristics and contexts in the physiological stress response and the utility of interpersonal methods in studying these associations are discussed.